Systems and methods of rerendering image hands to create a realistic grab experience in virtual reality/augmented reality environments

ABSTRACT

The technology disclosed relates to a method of realistic rendering of a real object as a virtual object in a virtual space using an offset in the position of the hand in a three-dimensional (3D) sensory space. An offset between expected positions of the eye(s) of a wearer of a head mounted device and a sensor attached to the head mounted device for sensing a position of at least one hand in a three-dimensional (3D) sensory space is determined. A position of the hand in the three-dimensional (3D) sensory space can be sensed using a sensor. The sensed position of the hand can be transformed by the offset into a re-rendered position of the hand as would appear to the wearer of the head mounted device if the wearer were looking at the actual hand. The re-rendered hand can be depicted to the wearer of the head mounted device.

RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 62/215,701, entitled “Systems and Methods ofRerendering Image Hands to Create a Realistic Grab Experience in VirtualReality/Augmented Reality Environments”, filed on 8 Sep. 2015, theentire contents of which are hereby incorporated by reference herein.

INCORPORATIONS

Materials incorporated by reference in this filing include thefollowing:

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BACKGROUND

The subject matter discussed in this section should not be assumed to beprior art merely as a result of its mention in this section. Similarly,a problem mentioned in this section or associated with the subjectmatter provided as background should not be assumed to have beenpreviously recognized in the prior art. The subject matter in thissection merely represents different approaches, which in and ofthemselves can also correspond to implementations of the claimedtechnology.

Conventional motion capture approaches rely on markers or sensors wornby the subject while executing activities and/or on the strategicplacement of numerous bulky and/or complex equipment in specialized andrigid environments to capture subject movements. Unfortunately, suchsystems tend to be expensive to construct. In addition, markers orsensors worn by the subject can be cumbersome and interfere with thesubject's natural movement. Further, systems involving large numbers ofcameras tend not to operate in real time, due to the volume of data thatneeds to be analyzed and correlated. Such considerations have limitedthe deployment and use of motion capture technology.

Consequently, there is a need for improved devices with greaterportability and techniques for capturing the motion of objects in realtime without fixed or difficult to configure sensors or markers.

BRIEF DESCRIPTION

In conventional VR development systems, grabbing or grasping a virtualobject provides an unrealistic experience. Presently, when provided withhand position information and virtual object dimensions/positioninformation, present VR modeling software (e.g., “Unity”(http://unity3d.com/industries/sim)) decides how the virtual objectreacts to the hand. When the hand closes around the object, such thatthe fingers are determined by Unity to have penetrated the object, Unityreturns a solution that the object will fly off into space away from thehand so that the hand's fingers can close. These felt unrealisticbecause people don't grasp things with more than 50% hand closure.

As yet, there were no easy ways to align augmented reality with the realworld. At the most fundamental level, this is because (1) the camerasused by the AR system are much closer together than human eyes, and (2)the cameras are positioned at an offset 1207 (of FIG. 12A) say 8centimeters in one example away from the user's actual eyes. This meansthat objects will appear larger than they actually are in reality. Thesetwo issues present barriers to creating truly immersive hybrid realityexperiences. Accordingly, in implementations, a whole new approach toimaging hands is provided that brings a user's real-life hands intoVR/AR.

As illustrated by FIG. 12B, in one implementation, imaged hands appearsignificantly larger than normal, because this is how they appear to thedevice cameras. Accordingly, in an implementation, a rebuilt version ofthe image of the user's hands can re-render the hands in 3D space,thereby allowing the hands to appear as they actually would in real lifefrom the perspective of the user's eyes. This effect is subtle to anoutside observer, but really powerful when experienced in VR/AR.

In one implementation, the technology disclosed determines realisticdisplacement of a virtual object to render a realistic representation ofa hand in a three-dimensional (3D) sensory space as a virtual object ina virtual space. An offset between expected positions of one or moreeyes of a wearer of a head mounted device and a sensor attached to thehead mounted device for sensing a first position of at least one hand ina three-dimensional (3D) sensory space can be determined. Someimplementations can include tracking fingers of the hand.

Using the sensor, a position of the hand in the three-dimensional (3D)sensory space can be sensed. Using the offset, the sensed position ofthe hand can be transformed into a re-rendered position of the hand aswould appear to the wearer of the head mounted device if the wearer werelooking at the actual hand. The re-rendered hand can be depicted to thewearer of the head mounted device.

In one implementation, the technology disclosed determines whether agrasp is intended for the virtual object based upon number of contactpoints (e.g., typically number of fingers) that the hand contacts theobject.

When one contact point is detected, a “nudge” is inferred. Thetechnology disclosed can compute an inertia for the virtual object andsends it skittering off into space.

When two contact points are detected, a “rotate” of the object isinferred. The technology disclosed can compute a position for the objectin space in which the contact points are preserved. This allows the userto rotate something (e.g. a phone for example) by touching it with twofingers. The phone will tend to “stick” to the fingers (i.e., an“artificial gravity”) until the fingers are pulled away.

When three or more contact points are detected, a “grasp” of the objectis inferred. The technology disclosed can compute a position for thevirtual object within the fingers that minimizes the extent that thehand's fingers penetrate the virtual object. In a presentimplementation, the technology disclosed can use a least squaresapproach applied to the contact points (e.g., square the differencesbetween penetration of finger into object from the old position of theobject and the new position of the object and add up the squares. Theposition of the object having a minimum sum for these square differencesis the solution returned.

The technology disclosed can support a two handed grasp of the object.The first hand to grasp the object is considered dominant. Anyconflicting solutions are resolved in favor of the dominant hand (e.g.,two solutions equally likely will be resolved in favor of the objectstaying in the dominant hand).

Example: Four fingers contact a cell phone virtual object. The cellphone is grasped. If the four fingers are on two hands, both hands graspthe phone.

Stretching—if fingers for each hand of a two hand grasp remain inrelative contact position but the hands are moved apart, the size of thevirtual object is extended in the direction that the hands are movedapart, effectively stretching the object.

Polymorphism—same scenario as above, but when object size passes athreshold defined for the object's class, the object morphs into alarger object. The larger object can be related to the original object(e.g., stretch the smartphone until it becomes a tablet) or can beunrelated (e.g., stretch the smartphone until it becomes a dragon) orhumorously related (e.g., stretch the smartphone and it becomes anantique telephone).

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to like partsthroughout the different views. Also, the drawings are not necessarilyto scale, with an emphasis instead generally being placed uponillustrating the principles of the disclosed technology. In thefollowing description, various implementations of the technologydisclosed are described with reference to the following drawings, inwhich:

FIG. 1 illustrates a system for capturing image and other sensory dataaccording to an implementation of the technology disclosed.

FIG. 1A illustrates one implementation of a one sub-component virtualcontact of a control object causing a virtual displacement of a virtualobject.

FIG. 1B illustrates one implementation of a two sub-component virtualcontact of a control object causing a virtual rotation of a virtualobject.

FIG. 1C illustrates one implementation of a three sub-component virtualcontact of a control object causing a virtual grasping of a virtualobject.

FIG. 2 is a simplified block diagram of a computer system implementingimage analysis suitable for supporting a virtual environment enabledapparatus according to an implementation of the technology disclosed.

FIG. 3A is a perspective view from the top of a sensor in accordancewith the technology disclosed, with motion sensors along an edge surfacethereof.

FIG. 3B is a perspective view from the bottom of a sensor in accordancewith the technology disclosed, with motion sensors along the bottomsurface thereof.

FIG. 3C is a perspective view from the top of a sensor in accordancewith the technology disclosed, with detachable motion sensors configuredfor placement on a surface.

FIG. 4 illustrates apparent movement of objects from the perspective ofthe user of a virtual environment enabled apparatus in accordance withthe technology disclosed.

FIG. 5 illustrates apparent movement of objects from the perspective ofthe user of a virtual environment enabled apparatus in accordance withthe technology disclosed.

FIG. 6 shows a flowchart of one implementation of determining motioninformation in a movable sensor apparatus.

FIG. 7 shows a flowchart of one implementation of applying movementinformation to apparent environment information sensed by the sensor toyield actual environment information in a movable sensor apparatus.

FIG. 8 illustrates one implementation of a system for providing avirtual device experience.

FIG. 9 shows a flowchart of one implementation of providing a virtualdevice experience.

FIG. 10 shows a flowchart of one implementation of cancelling drift in ahead mounted device (HMD).

FIGS. 11A, 11B, and 11C illustrate different implementations of a motionsensory integrated with a head mounted device (HMD).

FIG. 12A shows one implementation of a user interacting with a virtualreality/augmented reality environment using a motion sensor integratedwith a head mounted device (HMD).

FIG. 12B illustrates one implementation of a virtual reality/augmentedreality environment as viewed by a user in FIG. 12A.

FIG. 12C illustrates another implementation of a virtualreality/augmented reality environment as viewed by a user in FIG. 12A.

FIG. 13A shows one implementation of moving a motion sensor integratedwith a head mounted device (HMD) in response to body movements of a userdepicted in FIG. 12A.

FIG. 13B illustrates one implementation of a virtual reality/augmentedreality environment as viewed by a user in FIG. 13A.

FIG. 14 illustrates one implementation of generating a drift-adaptedvirtual reality/augmented reality environment responsive to motions of amotion sensor integrated with a head mounted device (HMD).

FIG. 15A illustrates an implementation of a 3D solid hand model withcapsule representation of predictive information of the hand.

FIGS. 15B and 15C illustrate different views of a 3D capsule handaccording to one implementation of the technology disclosed.

FIGS. 16A and 16B are simplified illustrations of fitting one or more 3Dsolid subcomponents to the observation information according to animplementation.

FIG. 17 illustrates an exemplary machine sensory and control system inone embodiment.

FIG. 18 depicts one embodiment of coupling emitters with other materialsor devices.

FIG. 19 shows one embodiment of interleaving arrays of image capturedevice(s).

FIG. 20 shows another embodiment of an exemplary machine sensory andcontrol system.

FIGS. 21 and 22 illustrate prediction information including models ofdifferent control objects.

FIGS. 23A and 23B show interaction between a control object and anengagement target.

FIG. 24 is an exemplary computing system according to an embodiment.

FIG. 25 illustrates a system for capturing image and other sensory dataaccording to an implementation of the technology disclosed.

FIG. 26 illustrates one implementation of finding points in an image ofan object being modeled.

FIGS. 27A and 27B graphically illustrates one implementation ofdetermining observation information.

FIG. 28 is a representative method of integrating real three-dimensional(3D) space sensing with a virtual reality head mounted device.

FIG. 29 depicts a flowchart of integrating real three-dimensional (3D)space sensing with an augmented reality head mounted device.

FIG. 30 illustrates a flowchart of a representative method ofintegrating real three-dimensional (3D) space sensing with a headmounted device that renders a virtual background and one or more virtualobjects is described.

FIG. 31 depicts a flowchart of re-rendering positional information of ahand in an augmented reality head mounted device.

DETAILED DESCRIPTION

The traditional paradigms of indirect interactions through standardinput devices such as mouse, keyboard, or stylus have their limitations,including skewed fields of view and restrictively receptive interfaces.Particularly in the VR/AR context, such traditional paradigms greatlydiminish the user experience. Accordingly, the technology disclosedallows users to interact with the virtual interfaces generated in VR/ARenvironment using free-form in-air gestures.

However, existing human-VR/AR systems interactions are very limited andunfeasible. Current VR/AR systems are complex as they force the user tointeract with VR/AR environment using a keyboard and mouse, or avocabulary of simply hand gestures. Further, despite strong academic andcommercial interest in VR/AR systems, VR/AR systems continue to becostly and requiring expensive equipment, and thus stand unsuitable forgeneral use by the average consumer.

An opportunity arises to provide an economical approach that providesadvantages of VR/AR for enhanced and sub-millimeter precisioninteraction with virtual objects without the draw backs of attaching ordeploying specialized hardware.

System and methods in accordance herewith generally utilize informationabout the motion of a control object, such as a user's hand, finger or astylus, in three-dimensional (3D) space to operate a physical or virtualuser interface and/or components thereof based on the motioninformation. Various implementations take advantage of motion-capturetechnology to track the motions of the control object in real time (ornear real time, i.e., sufficiently fast that any residual lag betweenthe control object and the system's response is unnoticeable orpractically insignificant). Other implementations can use syntheticmotion data (e.g., generated by a computer game) or stored motion data(e.g., previously captured or generated). References to motions in“free-form in-air”, “free-space”, “in-air”, or “touchless” motions orgestures are used herein with reference to an implementation todistinguish motions tied to and/or requiring physical contact of themoving object with a physical surface to effect input; however, in someapplications, the control object can contact a physical surfaceancillary to providing input, in such case the motion is stillconsidered a “free-form in-air” motion.

Examples of “free-form in-air” gestures include raising an arm, ormaking different poses using hands and fingers (e.g., ‘one fingerpoint’, ‘one finger click’, ‘two finger point’, ‘two finger click’,‘prone one finger point’, ‘prone one finger click’, ‘prone two fingerpoint’, ‘prone two finger click’, ‘medial one finger point’, ‘medial twofinger point’) to indicate an intent to interact. In otherimplementations, a point and grasp gesture can be used to move a cursoron a display of a device. In yet other implementations, “free-form”gestures can be a grip-and-extend-again motion of two fingers of a hand,grip-and-extend-again motion of a finger of a hand, holding a firstfinger down and extending a second finger, a flick of a whole hand,flick of one of individual fingers or thumb of a hand, flick of a set ofbunched fingers or bunched fingers and thumb of a hand, horizontalsweep, vertical sweep, diagonal sweep, a flat hand with thumb parallelto fingers, closed, half-open, pinched, curled, fisted, mime gun, okaysign, thumbs-up, ILY sign, one-finger point, two-finger point, thumbpoint, pinkie point, flat-hand hovering (supine/prone), bunged-fingershovering, or swirling or circular sweep of one or more fingers and/orthumb and/arm.

Further, in some implementations, a virtual environment can be definedto co-reside at or near a physical environment. For example, a virtualtouch screen can be created by defining a (substantially planar) virtualsurface at or near the screen of a display, such as an HMD, television,monitor, or the like. A virtual active table top can be created bydefining a (substantially planar) virtual surface at or near a table topconvenient to the machine receiving the input.

Among other aspects, implementations can enable quicker, crisper gesturebased or “free-form in-air” (i.e., not requiring physical contact)interfacing with a variety of machines (e.g., a computing systems,including HMDs, smart phones, desktop, laptop, tablet computing devices,special purpose computing machinery, including graphics processors,embedded microcontrollers, gaming consoles, audio mixers, or the like;wired or wirelessly coupled networks of one or more of the foregoing,and/or combinations thereof), obviating or reducing the need forcontact-based input devices such as a mouse, joystick, touch pad, ortouch screen.

Implementations of the technology disclosed also relate to methods andsystems that facilitate free-form in-air gestural interactions in avirtual reality (VR) and augmented reality (AR) environment. Thetechnology disclosed can be applied to solve the technical problem ofhow the user interacts with the virtual screens, elements, or controlsdisplayed in the VR/AR environment. Existing VR/AR systems restrict theuser experience and prevent complete immersion into the real world bylimiting the degrees of freedom to control virtual objects. Whereinteraction is enabled, it is coarse, imprecise, and cumbersome andinterferes with the user's natural movement. Such considerations ofcost, complexity and convenience have limited the deployment and use ofAR technology.

The systems and methods described herein can find application in avariety of computer-user-interface contexts, and can replace mouseoperation or other traditional means of user input as well as providenew user-input modalities. Free-form in-air control object motions andvirtual-touch recognition can be used, for example, to provide input tocommercial and industrial legacy applications (such as, e.g., businessapplications, including Microsoft Outlook™; office software, includingMicrosoft Office™, Windows™, Excel, etc.; graphic design programs;including Microsoft Visio™ etc.), operating systems such as MicrosoftWindows™; web applications (e.g., browsers, such as Internet Explorer™);other applications (such as e.g., audio, video, graphics programs,etc.), to navigate virtual worlds (e.g., in video games) or computerrepresentations of the real world (e.g., Google street view), or tointeract with three-dimensional virtual objects (e.g., Google Earth™).In some implementations, such applications can be run on HMDs or otherportable computer devices and thus can be similarly interacted withusing the free-form in-air gestures.

A “control object” or “object” as used herein with reference to animplementation is generally any three-dimensionally movable object orappendage with an associated position and/or orientation (e.g., theorientation of its longest axis) suitable for pointing at a certainlocation and/or in a certain direction. Control objects include, e.g.,hands, fingers, feet, or other anatomical parts, as well as inanimateobjects such as pens, styluses, handheld controls, portions thereof,and/or combinations thereof. Where a specific type of control object,such as the user's finger, is used hereinafter for ease of illustration,it is to be understood that, unless otherwise indicated or clear fromcontext, any other type of control object can be used as well.

A “virtual environment,” may also referred to as a “virtual construct,”“virtual touch plane,” or “virtual plane,” as used herein with referenceto an implementation denotes a geometric locus defined (e.g.,programmatically) in space and useful in conjunction with a controlobject, but not corresponding to a physical object; its purpose is todiscriminate between different operational modes of the control object(and/or a user-interface element controlled therewith, such as a cursor)based on whether the control object interacts the virtual environment.The virtual environment, in turn, can be, e.g., a virtual environment (aplane oriented relative to a tracked orientation of the control objector an orientation of a screen displaying the user interface) or a pointalong a line or line segment extending from the tip of the controlobject.

Using the output of a suitable motion-capture system or motioninformation received from another source, various implementationsfacilitate user input via gestures and motions performed by the user'shand or a (typically handheld) pointing device. For example, in someimplementations, the user can control the position of a cursor and/orother object on the interface of an HMD by with his index finger in thephysical environment outside the HMD's virtual environment, without theneed to touch the screen. The position and orientation of the fingerrelative to the HMD's interface, as determined by the motion-capturesystem, can be used to manipulate a cursor symbol. As will be readilyapparent to one of skill in the art, many other ways of mapping thecontrol object position and/or orientation onto a screen location can,in principle, be used; a particular mapping can be selected based onconsiderations such as, without limitation, the requisite amount ofinformation about the control object, the intuitiveness of the mappingto the user, and the complexity of the computation. For example, in someimplementations, the mapping is based on intersections with orprojections onto a (virtual) plane defined relative to the camera, underthe assumption that the HMD interface is located within that plane(which is correct, at least approximately, if the camera is correctlyaligned relative to the screen), whereas, in other implementations, thescreen location relative to the camera is established via explicitcalibration (e.g., based on camera images including the screen).

Aspects of the system and methods, described herein provide for improvedmachine interface and/or control by interpreting the motions (and/orposition, configuration) of one or more control objects or portionsthereof relative to one or more virtual environments defined (e.g.,programmatically) disposed at least partially within a field of view ofan image-capture device. In implementations, the position, orientation,and/or motion of control object(s) (e.g., a user's finger(s), thumb,etc.; a suitable hand-held pointing device such as a stylus, wand, orsome other control object; portions and/or combinations thereof) aretracked relative to the virtual environment to facilitate determiningwhether an intended free-form in-air gesture has occurred. Free-formin-air gestures can include engaging with a virtual control (e.g.,selecting a button or switch), disengaging with a virtual control (e.g.,releasing a button or switch), motions that do not involve engagementwith any virtual control (e.g., motion that is tracked by the system,possibly followed by a cursor, and/or a single object in an applicationor the like), environmental interactions (i.e., gestures to direct anenvironment rather than a specific control, such as scroll up/down),special-purpose gestures (e.g., brighten/darken screen, volume control,etc.), as well as others or combinations thereof.

Free-form in-air gestures can be mapped to one or more virtual controls,or a control-less screen location, of a display device associated withthe machine under control, such as an HMD. Implementations provide formapping of movements in three-dimensional (3D) space conveying controland/or other information to zero, one, or more controls. Virtualcontrols can include imbedded controls (e.g., sliders, buttons, andother control objects in an application), or environmental-levelcontrols (e.g., windowing controls, scrolls within a window, and othercontrols affecting the control environment). In implementations, virtualcontrols can be displayable using two-dimensional (2D) presentations(e.g., a traditional cursor symbol, cross-hairs, icon, graphicalrepresentation of the control object, or other displayable object) on,e.g., one or more display screens, and/or 3D presentations usingholography, projectors, or other mechanisms for creating 3Dpresentations. Presentations can also be audible (e.g., mapped tosounds, or other mechanisms for conveying audible information) and/orhaptic.

As used herein, a given signal, event or value is “responsive to” apredecessor signal, event or value of the predecessor signal, event orvalue influenced by the given signal, event or value. If there is anintervening processing element, step or time period, the given signal,event or value can still be “responsive to” the predecessor signal,event or value. If the intervening processing element or step combinesmore than one signal, event or value, the signal output of theprocessing element or step is considered “responsive to” each of thesignal, event or value inputs. If the given signal, event or value isthe same as the predecessor signal, event or value, this is merely adegenerate case in which the given signal, event or value is stillconsidered to be “responsive to” the predecessor signal, event or value.“Responsiveness” or “dependency” or “basis” of a given signal, event orvalue upon another signal, event or value is defined similarly.

As used herein, the “identification” of an item of information does notnecessarily require the direct specification of that item ofinformation. Information can be “identified” in a field by simplyreferring to the actual information through one or more layers ofindirection, or by identifying one or more items of differentinformation which are together sufficient to determine the actual itemof information. In addition, the term “specify” is used herein to meanthe same as “identify.”

Among other aspects, the technology described herein with reference toexample implementations can provide for automatically (e.g.,programmatically) cancelling out motions of a movable sensor configuredto capture motion and/or determining the path of an object based onimaging, acoustic or vibrational waves. Implementations can enablegesture detection, virtual reality and augmented reality, and othermachine control and/or machine communications applications usingportable devices, e.g., head mounted displays (HMDs), wearable goggles,watch computers, smartphones, and so forth, or mobile devices, e.g.,autonomous and semi-autonomous robots, factory floor material handlingsystems, autonomous mass-transit vehicles, automobiles (human or machinedriven), and so forth, equipped with suitable sensors and processorsemploying optical, audio or vibrational detection. In someimplementations, projection techniques can supplement the sensory basedtracking with presentation of virtual (or virtualized real) objects(visual, audio, haptic, and so forth) created by applications loadableto, or in cooperative implementation with, the HMD or other device toprovide a user of the device with a personal virtual experience (e.g., afunctional equivalent to a real experience).

Some implementations include optical image sensing. For example, asequence of images can be correlated to construct a 3-D model of theobject, including its position and shape. A succession of images can beanalyzed using the same technique to model motion of the object such asfree-form gestures. In low-light or other situations not conducive tooptical imaging, where free-form gestures cannot be recognized opticallywith a sufficient degree of reliability, audio signals or vibrationalwaves can be detected and used to supply the direction and location ofthe object as further described herein.

Other aspects and advantages of the present technology disclosed can beseen on review of the drawings, the detailed description and the claims,which follow.

One problem vexing researchers is the ability to determine when a realobject, such as the human hand is in “contact” with a virtual object invirtual reality and augmented reality situations. For example, FIG. 1Aillustrates one implementation 100A of a one sub-component virtualcontact of a control object causing a virtual displacement of a virtualobject 111. FIG. 1B illustrates one implementation 100B of a twosub-component virtual contact of a control object causing a virtualrotation of a virtual object 122B. FIG. 1C illustrates oneimplementation 100C of a three sub-component virtual contact of acontrol object causing a virtual grasping of a virtual object 122C.Another problem is that the sensors viewing real objects are disposedfrom the position of the wearer of AR/VR devices—leading to a parallaxerror. System feedback poses a yet further problem facing technologists.How can the wearer be alerted to the performance of the system withoutintrusively disrupting the AR/VR presentation. The technology describedwill address solutions to these and other issues in the AR/VRenvironment facing technologists.

Refer first to FIG. 1, which illustrates a system 100 for capturingimage data according to one implementation of the technology disclosed.System 100 is preferably coupled to a wearable device 101 that can be apersonal head mounted display (HMD) having a goggle form factor such asshown in FIG. 1, a helmet form factor, or can be incorporated into orcoupled with a watch, smartphone, or other type of portable device orany number of cameras 102, 104 coupled to sensory processing system 106.Cameras 102, 104 can be any type of camera, including cameras sensitiveacross the visible spectrum or with enhanced sensitivity to a confinedwavelength band (e.g., the infrared (IR) or ultraviolet bands); moregenerally, the term “camera” herein refers to any device (or combinationof devices) capable of capturing an image of an object and representingthat image in the form of digital data. For example, line sensors orline cameras rather than conventional devices that capture atwo-dimensional (2D) image can be employed. The term “light” is usedgenerally to connote any electromagnetic radiation, which may or may notbe within the visible spectrum, and may be broadband (e.g., white light)or narrowband (e.g., a single wavelength or narrow band of wavelengths).

Cameras 102, 104 are preferably capable of capturing video images (i.e.,successive image frames at a constant rate of at least 15 frames persecond); although no particular frame rate is required. The capabilitiesof cameras 102, 104 are not critical to the technology disclosed, andthe cameras can vary as to frame rate, image resolution (e.g., pixelsper image), color or intensity resolution (e.g., number of bits ofintensity data per pixel), focal length of lenses, depth of field, etc.In general, for a particular application, any cameras capable offocusing on objects within a spatial volume of interest can be used. Forinstance, to capture motion of the hand of an otherwise stationaryperson, the volume of interest might be defined as a cube approximatelyone meter on a side.

As shown, cameras 102, 104 can be oriented toward portions of a regionof interest 112 by motion of the device 101, in order to view avirtually rendered or virtually augmented view of the region of interest112 that can include a variety of virtual objects 116 as well as containan object of interest 114 (in this example, one or more hands) thatmoves within the region of interest 112. One or more sensors 108, 110capture motions of the device 101. In some implementations, one or morelight sources 115, 117 are arranged to illuminate the region of interest112. In some implementations, one or more of the cameras 102, 104 aredisposed opposite the motion to be detected, e.g., where the hand 114 isexpected to move. This is an optimal location because the amount ofinformation recorded about the hand is proportional to the number ofpixels it occupies in the camera images, and the hand will occupy morepixels when the camera's angle with respect to the hand's “pointingdirection” is as close to perpendicular as possible. Sensory processingsystem 106, which can be, e.g., a computer system, can control theoperation of cameras 102, 104 to capture images of the region ofinterest 112 and sensors 108, 110 to capture motions of the device 101.Information from sensors 108, 110 can be applied to models of imagestaken by cameras 102, 104 to cancel out the effects of motions of thedevice 101, providing greater accuracy to the virtual experiencerendered by device 101. Based on the captured images and motions of thedevice 101, sensory processing system 106 determines the position and/ormotion of object 114.

For example, as an action in determining the motion of object 114,sensory processing system 106 can determine which pixels of variousimages captured by cameras 102, 104 contain portions of object 114. Insome implementations, any pixel in an image can be classified as an“object” pixel or a “background” pixel depending on whether that pixelcontains a portion of object 114 or not. Object pixels can thus bereadily distinguished from background pixels based on brightness.Further, edges of the object can also be readily detected based ondifferences in brightness between adjacent pixels, allowing the positionof the object within each image to be determined. In someimplementations, the silhouettes of an object are extracted from one ormore images of the object that reveal information about the object asseen from different vantage points. While silhouettes can be obtainedusing a number of different techniques, in some implementations, thesilhouettes are obtained by using cameras to capture images of theobject and analyzing the images to detect object edges. Correlatingobject positions between images from cameras 102, 104 and cancelling outcaptured motions of the device 101 from sensors 108, 110 allows sensoryprocessing system 106 to determine the location in 3D space of object114, and analyzing sequences of images allows sensory processing system106 to reconstruct 3D motion of object 114 using conventional motionalgorithms or other techniques. See, e.g., U.S. patent application Ser.No. 13/414,485 (filed on Mar. 7, 2012) and U.S. Provisional PatentApplication Nos. 61/724,091 (filed on Nov. 8, 2012) and 61/587,554(filed on Jan. 7, 2012), the entire disclosures of which are herebyincorporated by reference.

Presentation interface 120 employs projection techniques in conjunctionwith the sensory based tracking in order to present virtual (orvirtualized real) objects (visual, audio, haptic, and so forth) createdby applications loadable to, or in cooperative implementation with, thedevice 101 to provide a user of the device with a personal virtualexperience. Projection can include an image or other visualrepresentation of an object.

One implementation uses motion sensors and/or other types of sensorscoupled to a motion-capture system to monitor motions within a realenvironment. A virtual object integrated into an augmented rendering ofa real environment can be projected to a user of a portable device 101.Motion information of a user body portion can be determined based atleast in part upon sensory information received from cameras 102, 104 oracoustic or other sensory devices. Control information is communicatedto a system based in part on a combination of the motion of the portabledevice 101 and the detected motion of the user determined from thesensory information received from cameras 102, 104 or acoustic or othersensory devices. The virtual device experience can be augmented in someimplementations by the addition of haptic, audio and/or other sensoryinformation projectors. For example, with reference to FIG. 8, optionalvideo projection mechanism 804 can project an image of a page (e.g.,virtual device 801) from a virtual book object superimposed upon a desk(e.g., surface portion 116) of a user; thereby creating a virtual deviceexperience of reading an actual book, or an electronic book on aphysical e-reader, even though no book or e-reader is present. Optionalhaptic projector 806 can project the feeling of the texture of the“virtual paper” of the book to the reader's finger. Optional audioprojector 802 can project the sound of a page turning in response todetecting the reader making a swipe to turn the page.

A plurality of sensors 108, 110 can coupled to the sensory processingsystem 106 to capture motions of the device 101. Sensors 108, 110 can beany type of sensor useful for obtaining signals from various parametersof motion (acceleration, velocity, angular acceleration, angularvelocity, position/locations); more generally, the term “motiondetector” herein refers to any device (or combination of devices)capable of converting mechanical motion into an electrical signal. Suchdevices can include, alone or in various combinations, accelerometers,gyroscopes, and magnetometers, and are designed to sense motions throughchanges in orientation, magnetism or gravity. Many types of motionsensors exist and implementation alternatives vary widely.

The illustrated system 100 can include any of various other sensors notshown in FIG. 1 for clarity, alone or in various combinations, toenhance the virtual experience provided to the user of device 101. Forexample, in low-light situations where free-form gestures cannot berecognized optically with a sufficient degree of reliability, system 106may switch to a touch mode in which touch gestures are recognized basedon acoustic or vibrational sensors. Alternatively, system 106 may switchto the touch mode, or supplement image capture and processing with touchsensing, when signals from acoustic or vibrational sensors are sensed.In still another operational mode, a tap or touch gesture may act as a“wake up” signal to bring the image and audio analysis system 106 from astandby mode to an operational mode. For example, the system 106 mayenter the standby mode if optical signals from the cameras 102, 104 areabsent for longer than a threshold interval.

It will be appreciated that the figures shown in FIG. 1 areillustrative. In some implementations, it may be desirable to house thesystem 100 in a differently shaped enclosure or integrated within alarger component or assembly. Furthermore, the number and type of imagesensors, motion detectors, illumination sources, and so forth are shownschematically for the clarity, but neither the size nor the number isthe same in all implementations.

Refer now to FIG. 2, which shows a simplified block diagram of acomputer system 200 for implementing sensory processing system 106.Computer system 200 includes a processor 202, a memory 204, a motiondetector and camera interface 206, a presentation interface 120,speaker(s) 209, a microphone(s) 210, and a wireless interface 211.Memory 204 can be used to store instructions to be executed by processor202 as well as input and/or output data associated with execution of theinstructions. In particular, memory 204 contains instructions,conceptually illustrated as a group of modules described in greaterdetail below, that control the operation of processor 202 and itsinteraction with the other hardware components. An operating systemdirects the execution of low-level, basic system functions such asmemory allocation, file management and operation of mass storagedevices. The operating system may include a variety of operating systemssuch as Microsoft WINDOWS operating system, the Unix operating system,the Linux operating system, the Xenix operating system, the IBM AIXoperating system, the Hewlett Packard UX operating system, the NovellNETWARE operating system, the Sun Microsystems SOLARIS operating system,the OS/2 operating system, the BeOS operating system, the MACINTOSHoperating system, the APACHE operating system, an OPENACTION operatingsystem, iOS, Android or other mobile operating systems, or anotheroperating system of platform.

The computing environment may also include otherremovable/non-removable, volatile/nonvolatile computer storage media.For example, a hard disk drive may read or write to non-removable,nonvolatile magnetic media. A magnetic disk drive may read from orwrites to a removable, nonvolatile magnetic disk, and an optical diskdrive may read from or write to a removable, nonvolatile optical disksuch as a CD-ROM or other optical media. Other removable/non-removable,volatile/nonvolatile computer storage media that can be used in theexemplary operating environment include, but are not limited to,magnetic tape cassettes, flash memory cards, digital versatile disks,digital video tape, solid state RAM, solid state ROM, and the like. Thestorage media are typically connected to the system bus through aremovable or non-removable memory interface.

Processor 202 may be a general-purpose microprocessor, but depending onimplementation can alternatively be a microcontroller, peripheralintegrated circuit element, a CSIC (customer-specific integratedcircuit), an ASIC (application-specific integrated circuit), a logiccircuit, a digital signal processor, a programmable logic device such asan FPGA (field-programmable gate array), a PLD (programmable logicdevice), a PLA (programmable logic array), an RFID processor, smartchip, or any other device or arrangement of devices that is capable ofimplementing the actions of the processes of the technology disclosed.

Motion detector and camera interface 206 can include hardware and/orsoftware that enables communication between computer system 200 andcameras 102, 104, as well as sensors 108, 110 (see FIG. 1). Thus, forexample, motion detector and camera interface 206 can include one ormore camera data ports 216, 218 and motion detector ports 217, 219 towhich the cameras and motion detectors can be connected (viaconventional plugs and jacks), as well as hardware and/or softwaresignal processors to modify data signals received from the cameras andmotion detectors (e.g., to reduce noise or reformat data) prior toproviding the signals as inputs to a motion-capture (“mocap”) program214 executing on processor 202. In some implementations, motion detectorand camera interface 206 can also transmit signals to the cameras andsensors, e.g., to activate or deactivate them, to control camerasettings (frame rate, image quality, sensitivity, etc.), to controlsensor settings (calibration, sensitivity levels, etc.), or the like.Such signals can be transmitted, e.g., in response to control signalsfrom processor 202, which may in turn be generated in response to userinput or other detected events.

Instructions defining mocap program 214 are stored in memory 204, andthese instructions, when executed, perform motion-capture analysis onimages supplied from cameras and audio signals from sensors connected tomotion detector and camera interface 206. In one implementation, mocapprogram 214 includes various modules, such as an object analysis module222 and a path analysis module 224. Object analysis module 222 cananalyze images (e.g., images captured via interface 206) to detect edgesof an object therein and/or other information about the object'slocation. In some implementations, object analysis module 222 can alsoanalyze audio signals (e.g., audio signals captured via interface 206)to localize the object by, for example, time distance of arrival,multilateration or the like. (“Multilateration is a navigation techniquebased on the measurement of the difference in distance to two or morestations at known locations that broadcast signals at known times. SeeWikipedia, athttp://en.wikipedia.org/w/index.php?title=Multilateration&oldid=523281858,on Nov. 16, 2012, 06:07 UTC). Path analysis module 224 can track andpredict object movements in 3D based on information obtained via thecameras. Some implementations will include a Virtual Reality(VR)/Augmented Reality (AR) environment manager 226 that providesintegration of virtual objects reflecting real objects (e.g., hand 114)as well as synthesized objects 116 for presentation to user of device101 via presentation interface 120 to provide a personal virtualexperience. One or more applications 228 can be loaded into memory 204(or otherwise made available to processor 202) to augment or customizefunctioning of device 101 thereby enabling the system 200 to function asa platform. Successive camera images are analyzed at the pixel level toextract object movements and velocities. Audio signals place the objecton a known surface, and the strength and variation of the signals can beused to detect object's presence. If both audio and image information issimultaneously available, both types of information can be analyzed andreconciled to produce a more detailed and/or accurate path analysis.

VR/AR environment manager 226 can include a number of components forgenerating a VR/AR environment. One component can be a camera such ascameras 102 or 104 or other video input to generate a digitized videoimage of the real world or user-interaction region. The camera can beany digital device that is dimensioned and configured to capture stillor motion pictures of the real world and to convert those images to adigital stream of information that can be manipulated by a computer. Forexample, cameras 102 or 104 can be digital still cameras, digital videocameras, web cams, head-mounted displays, phone cameras, tablet personalcomputers, ultra-mobile personal computers, and the like.

Another component can be a transparent, partially transparent, orsemi-transparent user interface such as a display of HMD 101 thatcombines rendered 3D virtual imagery with a view of the real world, sothat both are visible at the same time to a user. In someimplementations, the rendered 3D virtual imagery can projected usingholographic, laser, stereoscopic, auto-stereoscopic, or volumetric 3Ddisplays.

The VR/AR environment manager 226 can generate for display the virtualobjects automatically or in response to trigger events. For example, avirtual object may only appear when the user selects an icon or invokesan application presented across the VR/AR environment. In otherimplementations, the virtual object can be generated using a series ofunique real world markers. The markers can be of any design, including acircular, linear, matrix, variable bit length matrix, multi-levelmatrix, black/white (binary), gray scale patterns, and combinationsthereof. The markers can be two-dimensional or three-dimensional. Themarkers can be two- or three-dimensional barcodes, or two- orthree-dimensional renderings of real world, three-dimensional objects.For example, the markers can be thumbnail images of the virtual imagesthat are matched to the markers. The marker can also be an image of areal world item which the software has been programmed to recognize. So,for example, the software can be programmed to recognize a smart phoneor other item from a video stream of a book. The software thensuperimposes the virtual object in place of the smart phone device. Eachunique real world marker can correspond to a different virtual object,or a quality of a virtual object (e.g. the control's color, texture,opacity, adhesiveness, etc.) or both the virtual object itself and all(or a subset) of the qualities of the virtual object.

In some implementations, the VR/AR environment manager 226 can use anVR/AR library that serves as an image repository or database ofinteractive virtual objects, a computer 200 that can selectively searchand access the library, and a display (embedded within the HMD 101) or aprojector that is dimensioned and configured to display the real worlddigital image captured by a camera, as well as the virtual objectsretrieved from the VR/AR library. In some implementations, computer 200includes a search and return engine that links each unique real worldmarker to a corresponding virtual object in the VR/AR library.

In operation, a camera (e.g. 102, 104) returns a digital video stream ofthe real world, including images of one or more of the markers describedpreviously. Image samples are taken from the video stream and passed tothe computer 200 for processing. The search and return engine thensearches the VR/AR library for the virtual object that corresponds tothe marker images contained in the digital video stream of the realworld. Once a match is made between a real world marker contained in thedigital video stream and the VR/AR library, the AR library returns thevirtual object, its qualities, and its orientation for display across ascreen of the HMD 101. The virtual object is then superimposed upon thereal world space that comprises a digital marker in the form of a quickresponse (QR) code or RFID tags, according to one example. In otherimplementations, multiple markers can be used to position and orient asingle virtual control.

In yet other implementations, a “markerless” VR/AR experience can begenerated by identifying features of the surrounding real-world physicalenvironment via sensors such as gyroscopes, accelerometers, compasses,and GPS data such as coordinates.

Projected VR/AR allows users to simultaneously view the real wordphysical space and the virtual object superimposed in the space. In oneimplementation, a virtual object can be projected on to the real wordphysical space using micro-projectors embedded in wearable goggle orother head mounted display (like HMD 101) that cast a perspective viewof a stereoscopic 3D imagery onto the real world space. In such animplementation, a camera, in-between the micro-projectors can scan forinfrared identification markers placed in the real world space. Thecamera can use these markers to precisely track the user's head positionand orientation in the real word physical space, according to anotherimplementation. Yet another implementation includes usingretro-reflectors in the real word physical space to prevent scatteringof light emitted by the micro-projectors and to provision multi-userparticipation by maintaining distinct and private user views. In such animplementation, multiple users can simultaneously interact with the samevirtual object or with virtual controls that manipulate the same virtualobject, such that both the users view the same virtual objects andmanipulations to virtual objects by one user are seen by the other user,hence creating a collaborative environment.

In other implementations, projected VR/AR obviates the need of usingwearable hardware such as goggles and other hardware like displays tocreate an AR experience. In such implementations, a video projector,volumetric display device, holographic projector, and/or heads-updisplay can be used to create a “glasses-free” AR environment. See e.g.,holographic chip projectors available from Ostendo, a companyheadquartered in Carlsbad, Calif.(http://online.wsj.com/articles/new-chip-to-bring-holograms-to-smartphones-1401752938).In one implementation, such projectors can be electronically coupled touser computing devices such as HMDs, smart phones and can be configuredto produce and magnify virtual object and/or augmented virtual objectsthat are perceived as being overlaid on the real word physical space.

The sensory processing system 106, which captures a series ofsequentially temporal images of a region of interest 112. It furtheridentifies any gestures performed in the region of interest 112 orobjects in the region of interest 112 and controls responsiveness of therendered 3D virtual imagery to the performed gestures by updating the 3Dvirtual imagery based on the corresponding gestures.

Presentation interface 120, speakers 209, microphones 210, and wirelessnetwork interface 211 can be used to facilitate user interaction viadevice 101 with computer system 200. These components can be ofgenerally conventional design or modified as desired to provide any typeof user interaction. In some implementations, results of motion captureusing motion detector and camera interface 206 and mocap program 214 canbe interpreted as user input. For example, a user can perform handgestures or motions across a surface that are analyzed using mocapprogram 214, and the results of this analysis can be interpreted as aninstruction to some other program executing on processor 200 (e.g., aweb browser, word processor, or other application). Thus, by way ofillustration, a user might use upward or downward swiping gestures to“scroll” a webpage currently displayed to the user of device 101 viapresentation interface 120, to use rotating gestures to increase ordecrease the volume of audio output from speakers 209, and so on. Pathanalysis module 224 may represent the detected path as a vector andextrapolate to predict the path, e.g., to improve rendering of action ondevice 101 by presentation interface 120 by anticipating movement.

It will be appreciated that computer system 200 is illustrative and thatvariations and modifications are possible. Computer systems can beimplemented in a variety of form factors, including server systems,desktop systems, laptop systems, tablets, smart phones or personaldigital assistants, and so on. A particular implementation may includeother functionality not described herein, e.g., wired and/or wirelessnetwork interfaces, media playing and/or recording capability, etc. Insome implementations, one or more cameras and two or more microphonesmay be built into the computer rather than being supplied as separatecomponents. Further, an image or audio analyzer can be implemented usingonly a subset of computer system components (e.g., as a processorexecuting program code, an ASIC, or a fixed-function digital signalprocessor, with suitable I/O interfaces to receive image data and outputanalysis results).

While computer system 200 is described herein with reference toparticular blocks, it is to be understood that the blocks are definedfor convenience of description and are not intended to imply aparticular physical arrangement of component parts. Further, the blocksneed not correspond to physically distinct components. To the extentthat physically distinct components are used, connections betweencomponents (e.g., for data communication) can be wired and/or wirelessas desired. Thus, for example, execution of object analysis module 222by processor 202 can cause processor 202 to operate motion detector andcamera interface 206 to capture images and/or audio signals of an objecttraveling across and in contact with a surface to detect its entrance byanalyzing the image and/or audio data.

FIGS. 3A, 3B, and 3C illustrate three different configurations of amovable sensor system 300A-C, with reference to example implementationspackaged within a single housing as an integrated sensor. In all cases,sensor 300A, 300B, 300C includes a top surface 305, a bottom surface307, and a side wall 310 spanning the top and bottom surfaces 305, 307.With reference also to FIG. 3A, the top surface 305 of sensor 300Acontains a pair of windows 315 for admitting light to the cameras 102,104, one of which is optically aligned with each of the windows 315. Ifthe system includes light sources 115, 117, surface 305 may containadditional windows for passing light to the object(s) being tracked. Insensor 300A, motion sensors 108, 110 are located on the side wall 310.Desirably, the motion sensors are flush with the surface of side wall310 so that, the motion sensors are disposed to sense motions about alongitudinal axis of sensor 300A. Of course, the motion sensors can berecessed from side wall 310 internal to the device in order toaccommodate sensor operation and placement within available packagingspace so long as coupling with the external housing of sensor 300Aremains adequate. In sensor 300B, motion sensors 108, 110 are locatedproximate to the bottom surface 307, once again in a flush or recessedconfiguration. The top surface of the sensor 300B (not shown in thefigure for clarity sake) contains camera windows 315 as shown in FIG.3A. In FIG. 3C, motion sensors 108, 110 are external contact transducersthat connect to sensor 300C via jacks 320. This configuration permitsthe motion sensors to be located away from the sensor 300C, e.g., if themotion sensors are desirably spaced further apart than the packaging ofsensor 300C allows. In other implementations, movable sensor componentsof FIG. 2 can be imbedded in portable (e.g., head mounted displays(HMDs), wearable goggles, watch computers, smartphones, and so forth) ormovable (e.g., autonomous robots, material transports, automobiles(human or machine driven)) devices.

FIG. 4 illustrates apparent movement of objects from the perspective ofthe user of a virtual environment enabled apparatus 400 in accordancewith the technology. FIG. 4 shows two views of a user of a device 101viewing a field of view 113 at two different times. As shown in block401, at an initial time t₀, user is viewing field of view 113 a usingdevice 101 in a particular initial position to view an area 113 a. Asshown in block 402, device 101 presents to user a display of the devicefield of view 113 a that includes objects 114 (hands) in a particularpose. As shown in block 403, subsequently at time t₁, the user hasrepositioned device 101. Accordingly, the apparent position of objects114 in the field of view 113 b shown in block 404 has changed from theapparent position of the objects 114 in field of view 113 a. Even in thecase where the hands 114 did not move in space, the user sees anapparent movement of the hands 114 due to the change in position of thedevice.

Now with reference to FIG. 5, an apparent movement of one or more movingobjects from the perspective of the user of a virtual environmentenabled apparatus 500 is illustrated. As shown by block 502, field ofview 113 a presented by device 101 at time t₀ includes an object 114. Attime t₀, the position and orientation of tracked object 114 is knownwith respect to device reference frame 120 a, again at time t₀. As shownby block 404, at time t₁, the position and orientation of both devicereference frame 120 b and tracked object 114 have changed. As shown byblock 504, field of view 113 b presented by device 101 at time t₁includes object 114 in a new apparent position. Because the device 101has moved, the device reference frame 120 has moved from an original orstarting device reference frame 120 a to a current or final referenceframe 120 b as indicated by transformation T. It is noteworthy that thedevice 101 can rotate as well as translate. Implementations can providesensing the position and rotation of reference frame 120 b with respectto reference frame 120 a and sensing the position and rotation oftracked object 114 with respect to 120 b, at time t₁. Implementationscan determine the position and rotation of tracked object 114 withrespect to 120 a from the sensed position and rotation of referenceframe 120 b with respect to reference frame 120 a and the sensedposition and rotation of tracked object 114 with respect to 120 b.

In an implementation, a transformation R is determined that moves dashedline reference frame 120 a to dotted line reference frame 120 b, withoutintermediate conversion to an absolute or world frame of reference.Applying the reverse transformation R^(T) makes the dotted linereference frame 120 b lie on top of dashed line reference frame 120 a.Then the tracked object 114 will be in the right place from the point ofview of dashed line reference frame 120 a. (It is noteworthy that R^(T)is equivalent to R⁻¹ for our purposes.) In determining the motion ofobject 114, sensory processing system 106 can determine its location anddirection by computationally analyzing images captured by cameras 102,104 and motion information captured by sensors 108, 110. For example, anapparent position of any point on the object (in 3D space) at time t=t₀:

$\begin{bmatrix}x \\y \\z \\1\end{bmatrix},$can be converted to a real position of the point on the object at timet=t₁:

$\begin{bmatrix}x^{\prime} \\y^{\prime} \\z^{\prime} \\1\end{bmatrix}\quad$using an affine transform

$\begin{bmatrix}R_{ref} & T_{ref} \\0 & 1\end{bmatrix}\quad$from the frame of reference of the device. We refer to the combinationof a rotation and translation, which are not generally commutative, asthe affine transformation.

The correct location at time t=t₁ of a point on the tracked object withrespect to device reference frame 120 a is given by an inverse affinetransformation, e.g.,

$\begin{bmatrix}R_{ref}^{T} & {{- R_{ref}^{T}}*T_{ref}} \\0 & 1\end{bmatrix}\quad$as provided for in equation (1):

$\begin{matrix}{{\begin{bmatrix}R_{ref}^{T} & {\left( {- R_{ref}^{T}} \right)*T_{ref}} \\0 & 1\end{bmatrix}*\begin{bmatrix}x \\y \\z \\1\end{bmatrix}} = {\begin{bmatrix}x^{\prime} \\y^{\prime} \\z^{\prime} \\1\end{bmatrix}\quad}} & (1)\end{matrix}$

Where:

-   -   R_(ref) ^(T)—Represents the rotation matrix part of an affine        transform describing the rotation transformation from the device        reference frame 120 a to the device reference frame 120 b.    -   T_(ref)—Represents translation of the device reference frame 120        a to the device reference frame 120 b.

One conventional approach to obtaining the Affine transform R (from axisunit vector u=(u_(x), u_(y), u_(z)), rotation angle θ) method.Wikipedia, at http://en.wikipedia.org/wiki/Rotation_matrix, Rotationmatrix from axis and angle, on Jan. 30, 2014, 20:12 UTC, upon which thecomputations equation (2) are at least in part inspired:

$\begin{matrix}\begin{matrix}{R = \begin{bmatrix}{{\cos\mspace{11mu}\theta} + {u_{x}^{2}\left( {1 - \cos} \right)}} & {{u_{x}{u_{y}\left( {1 - {\cos\;\theta}} \right)}} - {u_{z}\sin\;\theta}} & {{u_{x}{u_{z}\left( {1 - {\cos\;\theta}} \right)}} + {u_{y}\sin\;\theta}} \\{{u_{y}{u_{x}\left( {1 - {\cos\;\theta}} \right)}} + {u_{z}\sin\;\theta}} & {{\cos\;\theta} + {u_{y}^{2}\left( {1 - {\cos\;\theta}} \right)}} & {{u_{y}{u_{z}\left( {1 - {\cos\;\theta}} \right)}} - {u_{x}\sin\;\theta}} \\{{u_{z}{u_{x}\left( {1 - {\cos\;\theta}} \right)}} - {u_{y}\sin\;\theta}} & {{u_{z}{y_{y}\left( {1 - {\cos\;\theta}} \right)}} + {u_{x}\sin\;\theta}} & {{\cos\;\theta} + {u_{z}^{2}\left( {1 - {\cos\;\theta}} \right)}}\end{bmatrix}} \\{R^{T} = \begin{bmatrix}{{\cos\;\theta} + {u_{x}^{2}\left( {1 - {\cos\;\theta}} \right)}} & {{u_{y}{u_{x}\left( {1 - {\cos\;\theta}} \right)}} + {u_{z}\sin\;\theta}} & {{u_{z}{u_{x}\left( {1 - {\cos\;\theta}} \right)}} - {u_{y}\sin\;\theta}} \\{{u_{x}{u_{y}\left( {1 - {\cos\;\theta}} \right)}} - {u_{z}\sin\;\theta}} & {{\cos\;\theta} + {u_{y}^{2}\left( {1 - {\cos\;\theta}} \right)}} & {{u_{z}{u_{y}\left( {1 - {\cos\;\theta}} \right)}} + {u_{x}\sin\;\theta}} \\{{u_{x}{u_{z}\left( {1 - {\cos\;\theta}} \right)}} + {u_{y}\sin\;\theta}} & {{u_{y}{u_{z}\left( {1 - {\cos\;\theta}} \right)}} - {u_{x}\sin\;\theta}} & {{\cos\;\theta} + {u_{z}^{2}\left( {1 - {\cos\;\theta}} \right)}}\end{bmatrix}} \\{{- R^{T}} = \begin{bmatrix}{{{- \cos}\;\theta} - {u_{x}^{2}\left( {1 - {\cos\;\theta}} \right)}} & {{{- u_{y}}{u_{x}\left( {1 - {\cos\;\theta}} \right)}} - {u_{z}\sin\;\theta}} & {{{- u_{z}}{u_{x}\left( {1 - {\cos\;\theta}} \right)}} + {u_{y}\sin\;\theta}} \\{{{- u_{x}}{u_{y}\left( {1 - {\cos\;\theta}} \right)}} + {u_{z}\sin\;\theta}} & {{{- \cos}\;\theta} - {u_{y}^{2}\left( {1 - {\cos\;\theta}} \right)}} & {{{- u_{z}}{u_{y}\left( {1 - {\cos\;\theta}} \right)}} - {u_{x}\sin\;\theta}} \\{{{- u_{x}}{u_{z}\left( {1 - {\cos\;\theta}} \right)}} - {u_{y}\sin\;\theta}} & {{{- u_{y}}{u_{z}\left( {1 - {\cos\;\theta}} \right)}} + {u_{x}\sin\;\theta}} & {{{- \cos}\;\theta} - {u_{z}^{2}\left( {1 - {\cos\;\theta}} \right)}}\end{bmatrix}}\end{matrix} & (2)\end{matrix}$

$T = \begin{bmatrix}a \\b \\c\end{bmatrix}$is a vector representing a translation of the object with respect toorigin of the coordinate system of the translated frame,

${{- R^{T}}*T} = \begin{bmatrix}{{\left( {{{- \cos}\;\theta} - {u_{x}^{2}\left( {1 - {\cos\;\theta}} \right)}} \right)(a)} + {\left( {{{- \cos}\;\theta} - {u_{y}^{2}\left( {1 - {\cos\;\theta}} \right)}} \right)(b)} + {\left( {{{- u_{z}}{u_{x}\left( {1 - {\cos\;\theta}} \right)}} + {u_{y}\sin\;\theta}} \right)(c)}} \\{{\left( {{{- u_{x}}{u_{y}\left( {1 - {\cos\;\theta}} \right)}} + {u_{z}\sin\;\theta}} \right)(a)} + {\left( {{{- \cos}\;\theta} - {u_{y}^{2}\left( {1 - {\cos\;\theta}} \right)}} \right)(b)} + {\left( {{{- u_{z}}{u_{y}\left( {1 - {\cos\;\theta}} \right)}} - {u_{x}\sin\;\theta}} \right)(c)}} \\{{\left( {{{- u_{x}}{u_{z}\left( {1 - {\cos\;\theta}} \right)}} - {u_{y}\sin\;\theta}} \right)(a)} + {\left( {{{- u_{y}}{u_{z}\left( {1 - {\cos\;\theta}} \right)}} + {u_{x}\sin\;\theta}} \right)(b)} + {\left( {{{- \cos}\;\theta} - {u_{z}^{2}\left( {1 - {\cos\;\theta}} \right)}} \right)(c)}}\end{bmatrix}$

In another example, an apparent orientation and position of the objectat time t=t₀: vector pair

$\begin{bmatrix}R_{obj} & T_{obj} \\0 & 1\end{bmatrix},$can be converted to a real orientation and position of the object attime t=t₁:

$\quad\begin{bmatrix}R_{obj}^{\prime} & T_{obj}^{\prime} \\0 & 1\end{bmatrix}$using an affine transform

$\quad{\quad{\begin{bmatrix}R_{ref} & T_{ref} \\0 & 1\end{bmatrix}.}}$The correct orientation and position of the tracked object with respectto device reference frame at time t=t₀ (120 a) is given by an inverseaffine transformation, e.g.,

$\quad\begin{bmatrix}R_{ref}^{T} & {{- R_{ref}^{T}}*T_{ref}} \\0 & 1\end{bmatrix}$as provided for in equation (3):

$\begin{matrix}{\quad{{\begin{bmatrix}R_{ref}^{T} & {\left( {- R_{ref}^{T}} \right)*T_{ref}} \\0 & 1\end{bmatrix}*\begin{bmatrix}R_{obj} & T_{obj} \\0 & 1\end{bmatrix}} = \begin{bmatrix}R_{obj}^{\prime} & T_{obj}^{\prime} \\0 & 1\end{bmatrix}}} & (3)\end{matrix}$

Where:

-   -   R^(T) _(ref)—Represents the rotation matrix part of an affine        transform describing the rotation transformation from the device        reference frame 120 a to the device reference frame 120 b.    -   R_(obj)—Represents a matrix describing the rotation at t₀ of the        object with respect to the device reference frame 120 b.    -   R′_(obj)—Represents a matrix describing the rotation at t₁ of        the object with respect to the device reference frame 120 a.    -   T_(ref)—Represents a vector translation of the device reference        frame 120 a to the device reference frame 120 b.    -   T_(obj)—Represents a vector describing the position at t₀ of the        object with respect to the device reference frame 120 b.    -   T′_(obj)—Represents a vector describing the position at at t₁ of        the object with respect to the device reference frame 120 a.

In a yet further example, an apparent orientation and position of theobject at time t=t₀: affine transform

$\quad{\begin{bmatrix}R_{obj} & T_{obj} \\0 & 1\end{bmatrix},}$can be converted to a real orientation and position of the object attime t=t₁:

$\quad{\quad\begin{bmatrix}R_{obj}^{\prime} & T_{obj}^{\prime} \\0 & 1\end{bmatrix}}$using an affine transform

$\quad{\begin{bmatrix}R_{ref} & T_{ref} \\0 & 1\end{bmatrix}.}$Furthermore, the position and orientation of the initial reference framewith respect to a (typically) fixed reference point in space can bedetermined using an affine transform

$\quad{\begin{bmatrix}R_{init} & T_{init} \\0 & 1\end{bmatrix}.}$The correct orientation and position of the tracked object with respectto device reference frame at time t=t₀ (120 a) is given by an inverseaffine transformation, e.g.,

$\quad\begin{bmatrix}R_{init}^{T} & {\left( {- R_{init}^{T}} \right)*T_{init}} \\0 & 1\end{bmatrix}$as provided for in equation (4):

$\begin{matrix}{{{\begin{bmatrix}R_{init}^{T} & {\left( {- R_{init}^{T}} \right)*T_{init}} \\0 & 1\end{bmatrix}\left\lbrack \begin{matrix}R_{ref}^{T} & {\left( {- R_{ref}^{T}} \right)*T_{ref}} \\0 & 1\end{matrix} \right\rbrack}*\begin{bmatrix}R_{obj} & T_{obj} \\0 & 1\end{bmatrix}} = \mspace{571mu}\left\lbrack \begin{matrix}R_{obj}^{\prime} & T_{obj}^{\prime} \\0 & 1\end{matrix} \right\rbrack} & (4)\end{matrix}$

Where:

-   -   R^(T) _(init)—Represents a rotation matrix part of an affine        transform describing the rotation transformation at t₀ from the        world reference frame 119 to the device reference frame 120 a.    -   R^(T) _(ref)—Represents the rotation matrix part of an affine        transform describing the rotation transformation from the device        reference frame 120 a to the device reference frame 120 b.    -   R_(obj)—Represents a matrix describing the rotation of the        object at t₀ with respect to the device reference frame 120 b.    -   R′_(obj)—Represents a matrix describing the rotation of the        object at t₁ with respect to the device reference frame 120 a.    -   T_(init)—Represents a vector translation at t₀ of the world        reference frame 119 to the device reference frame 120 a.    -   T_(ref)—Represents a vector translation at t₁ of the device        reference frame 120 a to the device reference frame 120 b.    -   T_(obj)—Represents a vector describing the position at t₀ of the        object with respect to the device reference frame 120 b.    -   T′_(obj)—Represents a vector describing the position at t₁ of        the object with respect to the device reference frame 120 a.        Detecting Motion Using Image Information

In some implementations, the technology disclosed can build a worldmodel with an absolute or world frame of reference. The world model caninclude representations of object portions (e.g. objects, edges ofobjects, prominent vortices) and potentially depth information whenavailable from a depth sensor, depth camera or the like, within theviewpoint of the virtual or augmented reality head mounted sensor. Thesystem can build the world model from image information captured by thecameras of the sensor. Points in 3D space can be determined from thestereo-image information are analyzed to obtain object portions. Thesepoints are not limited to a hand or other control object in aforeground; the points in 3D space can include stationary backgroundpoints, especially edges. The model is populated with the objectportions.

When the sensor moves (e.g., the wearer of a wearable headset turns herhead) successive stereo-image information is analyzed for points in 3Dspace. Correspondences are made between two sets of points in 3D spacechosen from the current view of the scene and the points in the worldmodel to determine a relative motion of the object portions. Therelative motion of the object portions reflects actual motion of thesensor.

Differences in points are used to determine an inverse transformation(the

$\quad\left( {{the}\mspace{14mu}\begin{bmatrix}R^{T} & {{- R^{T}}*T} \\0 & 1\end{bmatrix}} \right)$between model position and new position of object portions. In thisaffine transform, R^(T) describes the rotational portions of motionsbetween camera and object coordinate systems, and T describes thetranslational portions thereof.

The system then applies an inverse transformation of the objectcorresponding to the actual transformation of the device (since thesensor, not the background object moves) to determine the translationand rotation of the camera. Of course, this method is most effectivewhen background objects are not moving relative to the world frame(i.e., in free space).

The model can be updated whenever we detect new points not previouslyseen in the model. The new points are added to the model so that itcontinually grows.

Of course, embodiments can be created in which (1) device cameras areconsidered stationary and the world model is considered to move; or (2)the device cameras are considered to be moving and the world model isconsidered stationary.

Drift Cancellation

The use of a world model described above does not require anygyroscopic, accelerometer or magnetometer sensors, since the samecameras in a single unit (even the same cameras) can sense both thebackground objects and the control object. In any view where the systemcan recognize elements of the model, it can re-localize its position andorientation relative to the model and without drifting from sensor data.In some embodiments, motion sensors can be used to seed the frame toframe transformation and therefore bring correspondences between therendered virtual or augmented reality scenery closer to the sensedcontrol object, making the result less ambiguous (i.e., the system wouldhave an easier time determining what motion of the head had occurred toresult in the change in view from that of the model). In a yet furtherembodiment, sensor data could be used to filter the solution above sothat the motions appear to be smoother from frame to frame, while stillremaining impervious to drift caused by relying upon motion sensorsalone.

In some implementations, a Kabsch algorithm can be used to determine anoptimal rotation matrix given two paired sets of points. Referenceregarding Kabsch algorithm can be to Wikipedia, athttp://en.wikipedia.org/wiki/Kabsch_algorithm, Kabsch algorithm, on Feb.11, 2014, 07:30 UTC.

FIG. 6 shows a flowchart 600 of one implementation of determining motioninformation in a movable sensor apparatus. Flowchart 600 can beimplemented at least partially with a computer or other data processingsystem, e.g., by one or more processors configured to receive orretrieve information, process the information, store results, andtransmit the results. Other implementations may perform the actions indifferent orders and/or with different, fewer or additional actions thanthose illustrated in FIG. 6. Multiple actions can be combined in someimplementations. For convenience, this flowchart is described withreference to the system that carries out a method. The system is notnecessarily part of the method.

At action 610, a first positional information of a portable or movablesensor is determined with respect to a fixed point at a first time. Inone implementation, first positional information with respect to a fixedpoint at a first time t=t₀ is determined from one or motion sensorsintegrated with, or coupled to, a device including the portable ormovable sensor. For example, an accelerometer can be affixed to device101 of FIG. 1 or sensor 300 of FIG. 3, to provide accelerationinformation over time for the portable or movable device or sensor.Acceleration as a function of time can be integrated with respect totime (e.g., by sensory processing system 106) to provide velocityinformation over time, which can be integrated again to providepositional information with respect to time. In another example,gyroscopes, magnetometers or the like can provide information at varioustimes from which positional information can be derived. These items arewell known in the art and their function can be readily implemented bythose possessing ordinary skill. In another implementation, a secondmotion-capture sensor (e.g., such as sensor 300A-C of FIG. 3 forexample) is disposed to capture position information of the first sensor(e.g., affixed to 101 of FIG. 1 or sensor 300 of FIG. 3) to providepositional information for the first sensor.

At action 620, a second positional information of the sensor isdetermined with respect to the fixed point at a second time t=t₁.

At action 630, difference information between the first positionalinformation and the second positional information is determined.

At action 640, movement information for the sensor with respect to thefixed point is computed based upon the difference information. Movementinformation for the sensor with respect to the fixed point is can bedetermined using techniques such as discussed above with reference toequations (2).

At action 650, movement information for the sensor is applied toapparent environment information sensed by the sensor to remove motionof the sensor therefrom to yield actual environment information. Motionof the sensor can be removed using techniques such as discussed abovewith reference to FIGS. 4-5.

At action 660, actual environment information is communicated.

FIG. 7 shows a flowchart 700 of one implementation of applying movementinformation for the sensor to apparent environment information (e.g.,apparent motions of objects in the environment 112 as sensed by thesensor) to remove motion of the sensor therefrom to yield actualenvironment information (e.g., actual motions of objects in theenvironment 112 relative to the reference frame 120 a). Flowchart 700can be implemented at least partially with a computer or other dataprocessing system, e.g., by one or more processors configured to receiveor retrieve information, process the information, store results, andtransmit the results. Other implementations may perform the actions indifferent orders and/or with different, fewer or additional actions thanthose illustrated in FIG. 7. Multiple actions can be combined in someimplementations. For convenience, this flowchart is described withreference to the system that carries out a method. The system is notnecessarily part of the method.

At action 710, positional information of an object portion at the firsttime and the second time are captured.

At action 720, object portion movement information relative to the fixedpoint at the first time and the second time is computed based upon thedifference information and the movement information for the sensor.

At action 730, object portion movement information is communicated to asystem.

Some implementations will be applied to virtual reality or augmentedreality applications. For example, and with reference to FIG. 8, whichillustrates a system 800 for projecting a virtual device experience 801onto a surface medium 116 according to one implementation of thetechnology disclosed. System 800 includes a sensory processing system106 controlling a variety of sensors and projectors, such as for exampleone or more cameras 102, 104 (or other image sensors) and optionallysome illumination sources 115, 117 comprising an imaging system.Optionally, a plurality of vibrational (or acoustical) sensors 808, 810positioned for sensing contacts with surface 116 can be included.Optionally projectors under control of system 106 can augment thevirtual device experience 801, such as an optional audio projector 802to provide for example audio feedback, optional video projector 804, anoptional haptic projector 806 to provide for example haptic feedback toa user of virtual device experience 801. For further information onprojectors, reference may be had to “Visio-Tactile Projector” YouTube(https://www.youtube.com/watch?v=Bb0hNMxxewg) (accessed Jan. 15, 2014).In operation, sensors and projectors are oriented toward a region ofinterest 112, that can include at least a portion of a surface 116, orfree space 112 in which an object of interest 114 (in this example, ahand) moves along the indicated path 118.

FIG. 9 shows a flowchart 900 of one implementation of providing avirtual device experience. Flowchart 900 can be implemented at leastpartially with a computer or other data processing system, e.g., by oneor more processors configured to receive or retrieve information,process the information, store results, and transmit the results. Otherimplementations may perform the actions in different orders and/or withdifferent, fewer or additional actions than those illustrated in FIG. 9.Multiple actions can be combined in some implementations. Forconvenience, this flowchart is described with reference to the systemthat carries out a method. The system is not necessarily part of themethod.

At action 910, a virtual device is projected to a user. Projection caninclude an image or other visual representation of an object. Forexample, visual projection mechanism 804 of FIG. 8 can project a page(e.g., virtual device 801) from a book into a virtual environment 801(e.g., surface portion 116 or in space 112) of a reader; therebycreating a virtual device experience of reading an actual book, or anelectronic book on a physical e-reader, even though no book nor e-readeris present. In some implementations, optional haptic projector 806 canproject the feeling of the texture of the “virtual paper” of the book tothe reader's finger. In some implementations, optional audio projector802 can project the sound of a page turning in response to detecting thereader making a swipe to turn the page.

At action 920, using an accelerometer, moving reference frameinformation of a head mounted display (or hand-held mobile device)relative to a fixed point on a human body is determined.

At action 930, body portion movement information is captured. Motion ofthe body portion can be detected via sensors 108, 110 using techniquessuch as discussed above with reference to FIG. 6.

At action 940, control information is extracted based partly on the bodyportion movement information with respect to the moving reference frameinformation. For example, repeatedly determining movement informationfor the sensor and the object portion at successive times and analyzinga sequence of movement information can be used to determine a path ofthe object portion with respect to the fixed point. For example, a 3Dmodel of the object portion can be constructed from image sensor outputand used to track movement of the object over a region of space. Thepath can be compared to a plurality of path templates and identifying atemplate that best matches the path. The template that best matches thepath control information to a system can be used to provide the controlinformation to the system. For example, paths recognized from an imagesequence (or audio signal, or both) can indicate a trajectory of theobject portion such as a gesture of a body portion.

At action 950, control information can be communicated to a system. Forexample, a control information such as a command to turn the page of avirtual book can be sent based upon detecting a swipe along the desksurface of the reader's finger. Many other physical or electronicobjects, impressions, feelings, sensations and so forth can be projectedonto surface 116 (or in proximity thereto) to augment the virtual deviceexperience and applications are limited only by the imagination of theuser.

FIG. 10 shows a flowchart 1000 of one implementation of cancelling driftin a head mounted device (HMD). Flowchart 1000 can be implemented atleast partially with a computer or other data processing system, e.g.,by one or more processors configured to receive or retrieve information,process the information, store results, and transmit the results. Otherimplementations may perform the actions in different orders and/or withdifferent, fewer or additional actions than those illustrated in FIG.10. Multiple actions can be combined in some implementations. Forconvenience, this flowchart is described with reference to the systemthat carries out a method. The system is not necessarily part of themethod.

At action 1010, using an accelerometer, moving reference frameinformation of a head mounted display (or hand-held mobile device)relative to a fixed point on a human body is determined.

At action 1020, body portion movement information is captured.

At action 1030, control information is extracted based partly on thebody portion movement information with respect to the moving referenceframe information.

At action 1040, the control information is communicated to a system.

In some implementations, motion capture is achieved using an opticalmotion-capture system. In some implementations, object position trackingis supplemented by measuring a time difference of arrival (TDOA) ofaudio signals at the contact vibrational sensors and mapping surfacelocations that satisfy the TDOA, analyzing at least one image, capturedby a camera of the optical motion-capture system, of the object incontact with the surface, and using the image analysis to select amongthe mapped TDOA surface locations as a surface location of the contact.

Reference may be had to the following sources, incorporated herein byreference, for further information regarding computational techniques:

-   -   1. Wikipedia, at http://en.wikipedia.org/wiki/Euclidean_group,        on Nov. 4, 2013, 04:08 UTC;    -   2. Wikipedia, at        http://en.wikipedia.org/wiki/Affine_transformation, on Nov. 25,        2013, 11:01 UTC;    -   3. Wikipedia, at http://en.wikipedia.org/wiki/Rotation_matrix,        Rotation matrix from axis and angle, on Jan. 30, 2014, 20:12        UTC;    -   4. Wikipedia, at        http://en.wikipedia.org/wiki/Rotation_group_SO(3), Axis of        rotation, on Jan. 21, 2014, 21:21 UTC;    -   5. Wikipedia, at        http://en.wikipedia.org/wiki/Transformation_matrix, Affine        Transformations, on Jan. 28, 2014, 13:51 UTC; and    -   6. Wikipedia, at http://en.wikipedia.org/wiki/Axis %        E2%80%93angle_representation, on Jan. 25, 2014, 03:26 UTC.    -   7. Wikipedia, at http://en.wikipedia.org/wiki/Kabsch_algorithm,        Kabsch algorithm, on Feb. 11, 2014, 07:30 UTC.

FIGS. 11A, 11B, and 11C illustrate different implementations of a motionsensor 100 attached to a head mounted display 101. HMDs are wearabledevices that contain one or more displays positioned in the field ofvision of the user 1204 wearing the device 101. HMDs hold the promise ofbeing useful providers of virtual and augmented reality functionality.While popular conventional HMDs, such as “Google Glass” and “OculusRift” can be found in gaming applications, attempts to use HMDs inother, “more serious” applications have been wrought with difficulty anddrawbacks. One problem is that there is no practical mechanism toprovide user input to today's HMDs.

A user 1204 wearing a HMD 101 may have the desire to provide inputs to acomputer system in communication with the HMD 101 in order to selectamong options being displayed (e.g., menus, lists, icons and so forth),select virtual objects (such as 1214A, 1214B, 1314A, 1314B, 1414A,1414B) being displayed to view properties or obtain more information,add information to objects and other reasons. Unfortunately, however,addition of traditional input devices such as a mouse, joystick, touchpad, or touch screen, or the like would be cumbersome at best, robbingthe portability advantages from the wearable device. Speech input holdssome promise of providing non-contact based input to HMDs.Unfortunately, however, even commercial grade speech recognition systemshave disappointed. Furthermore, even if the speech input system were tofunction flawlessly, many users would be reticent to use it for fearthat it would have the appearance that they were talking to themselveswhen using the device. The so named “geek-chic” factor is lost.

Consequently, there is a need for enabling users of HMDs and similardevices to be able to provide input to a computer system withoutencumbrances.

Implementations of the technology disclosed address these and otherproblems by providing devices and methods for adding motion sensorycapabilities to HMDs, enabling users to provide command input to thedevice with gestures. An example implementation includes a motioncapture device 100 that is preferably attached to a wearable device 101that can be a personal head mounted display (HMD) having a goggle formfactor. Motion capture devices include systems for capturing image datathat may be used for detecting gestures, motions of objects and soforth. A motion capture device such as motion sensor 100 may include anynumber of cameras and radiation emitters coupled to a sensory processingsystem, as described above. The motion capture device can be used fordetecting gestures from a user which can be used as an input for acomputer system coupled with the HMD. In this application, the phrase“motion sensor” and “motion capture device” are used interchangeably.

In some implementations, the motion sensor 100 can be a motion-capturedevice (such as for example, a dual-camera motion controller as providedby Leap Motion, Inc., San Francisco, Calif. or other interfacingmechanisms and/or combinations thereof) that is positioned and orientedso as to monitor a region where hand motions normally take place.

In one implementation, a motion capture device 100 is operable to beattached to or detached from an adapter 1104, and the adapter 1104 isoperable to be attached to or detached from a HMD 101. The motioncapture device 100 is attached to the HMD 101 with an adapter 1104 in afixed position and orientation. In other implementations, the motioncapture device 100 is attached to the HMD 101 using a combination of theadapter 1104 and a mount bracket 1102. In implementations, including1100A, 1100B, and 1100C, the attachment mechanism coupling the adapter1104 to the HMD 101 utilizes existing functional or ornamental elementsof an HMD like HMD 101. Functional or ornamental elements of the HMDinclude; air vents, bosses, grooves, recessed channels, slots formedwhere two parts connect, openings for head straps and so forth.Advantageously using existing features of the HMD to attach the adapter1104 obviates any need to modify the design of the HMD to attach amotion capture device.

Advantageously, coupling the motion capture device 100 to the HMD 101enables gesture recognition while the user 1204 is wearing the HMD 101.Further, implementations can provide improved interfacing with computingsystems, such as using the motion capture device 100 to detect motion ofthe HMD 101. With these advantages there is a reduced need forcontact-based input devices and stationary contactless input devices.

In yet other implementations, the motion capture device 100 is embeddedwithin the HMD 101 and not separately attached to the HMD 101, such thatthe HMD 101 and the motion capture device 100 are part of one systemalong with other components of the HMD 101.

FIG. 12A shows one implementation 1200A of a user 1204 interacting witha virtual reality/augmented reality environment 1206 of the HMD 101using a motion sensor 100 integrated with a HMD 101. In FIG. 12A, theuser 1204 wears the HMD 101 and begins interacting with the VR/ARenvironment 1206 presented across a display/interface of the HMD 101. Insome implementations, the display/interface of the HMD 101 can includevirtual objects as part of applications, programs, operating system APIs(which mimic and are analogous to pre-existing “windows, icons, menus,pointer” (WIMP) interactions and operating system kernel) browsers,videos, images, etc.

In FIG. 12A, the user 1204 can operate a virtual environment (such as1206, 1306 and 1406) generated by the HMD 101 and viewed by the user1204 in intuitive ways using free-form in-air gestures that areperformed in the real word physical space by the user's hands 114 orotherwise. For example, gestures can be used to perform traditionalmanipulations of virtual files, folders, text editors, spreadsheets,databases, paper sheets, recycling bin, windows, or clipboards thatrepresent their pre-existing counterparts. Such manipulations caninclude—the user picking up a virtual object and bringing it to theirdesired destination, running searches or flipping through with theirhands and find what is need, trashing unwanted virtual items by pickingthem and dropping them into the virtual recycling bin, pointing towardsvirtual song files to be played, pulling a blank virtual paper and begintyping, pulling-down a virtual menu, selecting a virtual icon, rotatinga 3D image for 360 degree inspection, moving forward into the windowsenvelope with a forward sweep, moving backward into the windows envelopewith a backward sweep, bringing in contact a first file icon with anapplication or program icon using a two-hand inward swipe to open thecorresponding file with the application or program, and the like.

FIG. 12B illustrates one implementation 1200B of a virtualreality/augmented reality environment as viewed by a user in FIG. 12A.In particular, FIG. 12B shows an example of rendered 3D virtual imageryin a virtual environment 1206. In various implementations, virtualenvironment 1206 is generated using real-time rendering techniques suchas orthographic or perspective projection, clipping, screen mapping,and/or rasterizing and is transformed into the field of view of a livecamera embedded in the motion sensor 100, HMD 101 or another motionsensor, HMD, video projector, holographic projection system, smartphone,wearable goggle, or heads up display (HUD). In some otherimplementations, transforming models into the current view space of theuser 1204 can be accomplished using sensor output from onboard sensors.For example, gyroscopes, magnetometers and other motion sensors canprovide angular displacements, angular rates and magnetic readings withrespect to a reference coordinate frame, and that data can be used by areal-time onboard rendering engine to generate the 3D virtual imagery.If the user 1204 physically moves the HMD 101, resulting in a change ofview of the embedded camera, the virtual environment 1206 and the 3Dvirtual imagery can be updated accordingly using the sensor data.

In some implementations, virtual environment 1206 can include a varietyof information from a variety of local or network information sources.Some examples of information include specifications, directions,recipes, data sheets, images, video clips, audio files, schemas, userinterface elements, thumbnails, text, references or links, telephonenumbers, blog or journal entries, notes, part numbers, dictionarydefinitions, catalog data, serial numbers, order forms, marketing oradvertising, icons associated with objects managed by an OS, and anyother information that may be useful to a user. Some examples ofinformation resources include local databases or cache memory, networkdatabases, Websites, online technical libraries, other devices, or anyother information resource that can be accessed by user computingdevices either locally or remotely through a communication link.

Virtual objects (such as 1214A, 1214B, 1314A, 1314B, 1414A, 1414B) caninclude text, images, or references to other information (e.g., links).In one implementation, virtual objects can be displayed proximate totheir corresponding real-world objects (e.g. hand 114). In anotherimplementation, virtual objects can describe or otherwise provide usefulinformation about the objects to a user. Some other implementationsinclude the virtual objects representing other and/or different realworld products such as furniture (chairs, couches, tables, etc.),kitchen appliances (stoves, refrigerators, dishwashers, etc.), officeappliances (copy machines, fax machines, computers), consumer andbusiness electronic devices (telephones, scanners, etc.), furnishings(pictures, wall hangings, sculpture, knick knacks, plants), fixtures(chandeliers and the like), cabinetry, shelving, floor coverings (tile,wood, carpets, rugs), wall coverings, paint colors, surface textures,countertops (laminate, granite, synthetic countertops), electrical andtelecommunication jacks, audio-visual equipment, speakers, hardware(hinges, locks, door pulls, door knobs, etc.), exterior siding, decking,windows, shutters, shingles, banisters, newels, hand rails, stair steps,landscaping plants (trees, shrubs, etc.), and the like, and qualities ofall of these (e.g. color, texture, finish, etc.).

In operation, the technology disclosed detects presence and motion ofthe hands 114 in the real world physical and responsively createscorresponding virtual representations 1214A and 1214B in the virtualenvironment 1206, which are viewable by the user 1204. FIG. 13A showsone implementation 1300A in which the motion sensor 100 that isintegrated with the HMD 101 moves in response to body movements of user1204.

In FIG. 12C, another implementation 1200C of a virtual reality/augmentedreality environment as viewed by a user in FIG. 12A is shown. Inimplementation 1200C, virtual representations 1214A and 1214B of FIG.12B have been re-rendered, yielding more realistic image hands 1214C byapplication of a method such as illustrated by FIG. 31.

In the example shown in FIG. 13A, the user 1204 turns his head 1202causing the HMD 101 and the attached motion sensor 100 to move. Themotion of the attached motion sensor 100 causes a change in thereference frame of the HMD 101, resulting in an updated virtualenvironment 1306 of the HMD 101.

FIG. 13B illustrates one implementation 1300B of the updated virtualenvironment 1306. It should be noted that at this juncture the hands 114have not moved from their initial position and orientation illustratedin FIGS. 12A and 12B. However, the updated virtual environment 1306generates erroneous virtual representations 1314A and 1314B based on themovement of the motion sensor 100.

Dependence of the determination of the positions and orientations of thehands 114, and in turn that of their corresponding virtualrepresentations, on the motion of the motion sensor 100 is describedwith reference to FIG. 26, 27A, 27B. The motion sensor 100 includes thecameras 102, 104, whose location is determinative factor in thecalculation of the positions and orientations of the hands 114, asdescribed below.

FIG. 26 illustrates an implementation 2600 of finding points in an imageof an object being modeled. Now with reference to block 2635 of FIG. 26,cameras 102, 104 are operated to collect a sequence of images (e.g.,2610A, 2610B) of the object 114. The images are time correlated suchthat an image from camera 102 can be paired with an image from camera104 that was captured at the same time (or within a few milliseconds).These images are then analyzed by an object detection module thatdetects the presence of one or more objects 2650 in the image, and anobject analysis module analyzes detected objects to determine theirpositions and shape in 3D space. If the received images 2610A, 2610Binclude a fixed number of rows of pixels (e.g., 1080 rows), each row canbe analyzed, or a subset of the rows can be used for faster processing.Where a subset of the rows is used, image data from adjacent rows can beaveraged together, e.g., in groups of two or three.

Again with reference to block 2635 in FIG. 26, one or more rays 2652 canbe drawn from the camera(s) proximate to an object 114 for some pointsP, depending upon the number of vantage points that are available. Oneor more rays 2652 can be determined for some point P on a surface of theobject 2650 in image 2610A. A tangent 2656 to the object surface at thepoint P can be determined from point P and neighboring points. A normalvector 2658 to the object surface 2650 at the point P is determined fromthe ray and the tangent by cross product or other analogous technique.In block 2668, a model portion (e.g., capsule 2687) can be aligned toobject surface 2650 at the point P based upon the normal vector 2658 anda normal vector 2659 of the model portion 2672. Optionally, as shown inblock 2635, a second ray 2654 is determined to the point P from a secondimage 2610B captured by a second camera. In some instances, fewer oradditional rays or constraints from neighboring capsule placements cancreate additional complexity or provide further information. In block2666, additional information from placing neighboring capsules can beused as constraints to assist in determining a solution for placing thecapsule. For example, using one or more parameters from a capsule fit toa portion of the object adjacent to the capsule being placed, e.g.,angles of orientation, the system can determine a placement, orientationand shape/size information for the capsule. Object portions with toolittle information to analyze can be discarded or combined with adjacentobject portions. In block 2667, one or more illumination sources 2672can provide controlled or structured lighting to enhance image captureof hand 114.

FIGS. 27A and 27B graphically illustrates one implementation ofdetermining observation information 2700A and 2700B. In animplementation, comparing predictive information to observationinformation can be achieved by selecting one or more sets of points inspace surrounding or bounding the control object within a field of viewof one or more image capture device(s). As shown by FIG. 27A, points inspace can be determined using one or more sets of lines 2704, 2714,2724, 2734 originating at point(s) of view 2732, 2702 associated withthe image capture device(s) (e.g., FIG. 1: 102, 104) and determiningtherefrom one or more intersection point(s) defining a bounding region(i.e., region formed by lines FIG. 27B: 2741, 2742, 2743, and 2744)surrounding a cross-section of the control object. The bounding regioncan be used to define a virtual surface (FIG. 27A: 2746 a, 2746 b, 2746c) to which model subcomponents can be compared. In an implementation,the virtual surface can include straight portions, curved surfaceportions, and/or combinations thereof.

The technology disclosed solves this technical problem by applying acorrection that prevents the HMD 101 from displaying such erroneousvirtual representations and instead generate virtual representationsthat accurately corresponding to the actual positions and orientationsof the hands 114 in the real world physical space.

FIG. 14 illustrates one implementation 1400 of generating adrift-adapted virtual reality/augmented reality environment 1406 of theHMD 101 responsive to motions of a motion sensor 100 integrated with theHMD 101. In particular, FIG. 14 shows that virtual representations 1414Aand 1414B correspond to the actual positions and orientations of thehands 114 in the real world physical space even when the HMD 101 hasgenerated an updated virtual environment 1306 responsive to the movementof the motion sensor 100.

A gesture-recognition system recognizes gestures for purposes ofproviding input to the electronic device, but can also capture theposition and shape of the user's hand in consecutive video images inorder to characterize a hand gesture in 3D space and reproduce it on thedisplay screen. A 3D model of the user's hand is determined from a solidhand model covering one or more capsule elements built from the imagesusing techniques described below with reference to FIGS. 15A-15C.

FIG. 15A shows one implementation of a 3D solid hand model 1500A withcapsule representation of predictive information of the hand. Someexamples of predictive information of the hand include finger segmentlength, distance between finger tips, joint angles between fingers, andfinger segment orientation. As illustrated by FIG. 15A, the predictioninformation 1520 can be constructed from one or more model subcomponentsreferred to as capsules 1530, 1532, and 1534, which are selected and/orconfigured to represent at least a portion of a surface of the hand andvirtual surface portion 1522. In some implementations, the modelsubcomponents can be selected from a set of radial solids, which canreflect at least a portion of the hand in terms of one or more ofstructure, motion characteristics, conformational characteristics, othertypes of characteristics of hand, and/or combinations thereof. In oneimplementation, radial solids are objects made up of a 1D or 2Dprimitive (e.g., line, curve, plane) and a surface having a constantradial distance to the 1D or 2D primitive. A closest point to the radialsolid can be computed relatively quickly. As used herein, three orgreater capsules are referred to as a “capsoodle.”

In an implementation, observation information including observation ofthe control object can be compared against the model at one or more ofperiodically, randomly or substantially continuously (i.e., in realtime). A “control object” as used herein with reference to animplementation is generally any three-dimensionally movable object orappendage with an associated position and/or orientation (e.g., theorientation of its longest axis) suitable for pointing at a certainlocation and/or in a certain direction. Control objects include, e.g.,hands, fingers, feet, or other anatomical parts, as well as inanimateobjects such as pens, styluses, handheld controls, portions thereof,and/or combinations thereof. Where a specific type of control object,such as the user's finger, is used hereinafter for ease of illustration,it is to be understood that, unless otherwise indicated or clear fromcontext, any other type of control object can be used as well.

Observational information can include without limitation observed valuesof attributes of the control object corresponding to the attributes ofone or more model subcomponents in the predictive information for thecontrol object. In an implementation, comparison of the model with theobservation information provides an error indication. In animplementation, an error indication can be computed by determining aclosest distance determined between a first point A belonging to a setof points defining the virtual surface 1522 and a second point Bbelonging to a model subcomponent 1530 determined to be corresponding tothe first point (e.g., nearest to the first point for example). In animplementation, the error indication can be applied to the predictiveinformation to correct the model to more closely conform to theobservation information. In an implementation, error indication can beapplied to the predictive information repeatedly until the errorindication falls below a threshold, a measure of conformance with theobservation information rises above a threshold, or a fixed or variablenumber of times, or a fixed or variable number of times per time period,or combinations thereof.

In one implementation and with reference to FIGS. 15B and 15C, acollection of radial solids and/or capsuloids can be considered a“capsule hand.” In particular, FIGS. 15B and 15C illustrate differentviews 1500B and 1500C of a 3D capsule hand. A number of capsuloids 1572,e.g. five (5), are used to represent fingers on a hand while a number ofradial solids 1574 are used to represent the shapes of the palm andwrist.

FIGS. 17-20 illustrate an exemplary machine sensory and control system(MSCS) in implementations.

In one implementation, a motion sensing and controller system providesfor detecting that some variation(s) in one or more portions of interestof a user has occurred, for determining that an interaction with one ormore machines corresponds to the variation(s), for determining if theinteraction should occur, and, if so, for affecting the interaction. TheMachine Sensory and Control System (MSCS) typically includes a portiondetection system, a variation determination system, an interactionsystem and an application control system.

As FIG. 17 shows, one detection system 90A implementation includes anemission module 91, a detection module 92, a controller 96, a processingmodule 94 and a machine control module 95. In one implementation andwith reference to FIG. 18, the emission module includes one or moreemitter(s) 180A, 180B (e.g., LEDs or other devices emitting light in theIR, visible, or other spectrum regions, or combinations thereof; radioand/or other electromagnetic signal emitting devices) that arecontrollable via emitter parameters (e.g., frequency, activation state,firing sequences and/or patterns, etc.) by the controller 96. However,other existing/emerging emission mechanisms and/or some combinationthereof can also be utilized in accordance with the requirements of aparticular implementation. The emitters 180A, 180B can be individualelements coupled with materials or devices 182 (and/or materials) (e.g.,lenses 182A, multi-lenses 182B (of FIG. 18), image directing film (IDF)182C (of FIG. 18), liquid lenses, combinations thereof, and/or others)with varying or variable optical properties to direct the emission, oneor more arrays 180C of emissive elements (combined on a die orotherwise), with or without the addition of devices 182C for directingthe emission, or combinations thereof, and positioned within an emissionregion 181 (of FIG. 18) according to one or more emitter parameters(i.e., either statically (e.g., fixed, parallel, orthogonal or formingother angles with a work surface, one another or a display or otherpresentation mechanism) or dynamically (e.g., pivot, rotate and/ortranslate) mounted, embedded (e.g., within a machine or machinery undercontrol) or otherwise coupleable using an interface (e.g., wired orwireless)). In some implementations, structured lighting techniques canprovide improved surface feature capture capability by castingillumination according to a reference pattern onto the object 98. Imagecapture techniques described in further detail herein can be applied tocapture and analyze differences in the reference pattern and the patternas reflected by the object 98. In yet further implementations, detectionsystem 90A may omit emission module 91 altogether (e.g., in favor ofambient lighting).

In one implementation and with reference to FIG. 19, the detectionmodule 92 includes one or more capture device(s) 190A, 190B (e.g., light(or other electromagnetic radiation sensitive devices) that arecontrollable via the controller 96. The capture device(s) 190A, 190B cancomprise individual or multiple arrays of image capture elements 190A(e.g., pixel arrays, CMOS or CCD photo sensor arrays, or other imagingarrays) or individual or arrays of photosensitive elements 190B (e.g.,photodiodes, photo sensors, single detector arrays, multi-detectorarrays, or other configurations of photo sensitive elements) orcombinations thereof. Arrays of image capture device(s) 190C (of FIG.19) can be interleaved by row (or column or a pattern or otherwiseaddressable singly or in groups). However, other existing/emergingdetection mechanisms and/or some combination thereof can also beutilized in accordance with the requirements of a particularimplementation. Capture device(s) 190A, 190B each can include aparticular vantage point 190-1 from which objects 98 within area ofinterest 5 are sensed and can be positioned within a detection region191 (of FIG. 19) according to one or more detector parameters (i.e.,either statically (e.g., fixed, parallel, orthogonal or forming otherangles with a work surface, one another or a display or otherpresentation mechanism) or dynamically (e.g. pivot, rotate and/ortranslate), mounted, embedded (e.g., within a machine or machinery undercontrol) or otherwise coupleable using an interface (e.g., wired orwireless)). Capture devices 190A, 190B can be coupled with devices 192A,192B, 192C (and/or materials) (of FIG. 19) (e.g., lenses 192A (of FIG.19), multi-lenses 192B (of FIG. 19), image directing film (IDF) 192C (ofFIG. 19), liquid lenses, combinations thereof, and/or others) withvarying or variable optical properties for directing the reflectance tothe capture device for controlling or adjusting resolution, sensitivityand/or contrast. Capture devices 190A, 190B can be designed or adaptedto operate in the IR, visible, or other spectrum regions, orcombinations thereof; or alternatively operable in conjunction withradio and/or other electromagnetic signal emitting devices in variousapplications. In an implementation, capture devices 190A, 190B cancapture one or more images for sensing objects 98 and capturinginformation about the object (e.g., position, motion, etc.). Inimplementations comprising more than one capture device, particularvantage points of capture devices 190A, 190B can be directed to area ofinterest 5 so that fields of view 190-2 of the capture devices at leastpartially overlap. Overlap in the fields of view 190-2 providescapability to employ stereoscopic vision techniques (see, e.g., FIG.19), including those known in the art to obtain information from aplurality of images captured substantially contemporaneously.

While illustrated with reference to a particular implementation in whichcontrol of emission module 91 and detection module 92 are co-locatedwithin a common controller 96, it should be understood that thesefunctions will be separate in some implementations, and/or incorporatedinto one or a plurality of elements comprising emission module 91 and/ordetection module 92 in some implementations. Controller 96 comprisescontrol logic (hardware, software or combinations thereof) to conductselective activation/de-activation of emitter(s) 180A, 180B (and/orcontrol of active directing devices) in on-off, or other activationstates or combinations thereof to produce emissions of varyingintensities in accordance with a scan pattern which can be directed toscan an area of interest 5. Controller 96 can comprise control logic(hardware, software or combinations thereof) to conduct selection,activation and control of capture device(s) 190A, 190B (and/or controlof active directing devices) to capture images or otherwise sensedifferences in reflectance or other illumination. Signal processingmodule 94 determines whether captured images and/or sensed differencesin reflectance and/or other sensor 93—perceptible phenomena indicate apossible presence of one or more objects of interest 98, includingcontrol objects 99, the presence and/or variations thereof can be usedto control machines and/or other applications 95.

In various implementations, the variation of one or more portions ofinterest of a user can correspond to a variation of one or moreattributes (position, motion, appearance, surface patterns) of a userhand 99, finger(s), points of interest on the hand 99, facial portion 98other control objects (e.g., styli, tools) and so on (or somecombination thereof) that is detectable by, or directed at, butotherwise occurs independently of the operation of the machine sensoryand control system. Thus, for example, the system is configurable to‘observe’ ordinary user locomotion (e.g., motion, translation,expression, flexing, deformation, and so on), locomotion directed atcontrolling one or more machines (e.g., gesturing, intentionallysystem-directed facial contortion, etc.), attributes thereof (e.g.,rigidity, deformation, fingerprints, veins, pulse rates and/or otherbiometric parameters). In one implementation, the system provides fordetecting that some variation(s) in one or more portions of interest(e.g., fingers, fingertips, or other control surface portions) of a userhas occurred, for determining that an interaction with one or moremachines corresponds to the variation(s), for determining if theinteraction should occur, and, if so, for at least one of initiating,conducting, continuing, discontinuing and/or modifying the interactionand/or a corresponding interaction.

For example and with reference to FIG. 20, a variation determinationsystem 90B implementation comprises a model management module 197 thatprovides functionality to build, modify, customize one or more models torecognize variations in objects, positions, motions and attribute stateand/or change in attribute state (of one or more attributes) fromsensory information obtained from detection system 90A. A motion captureand sensory analyzer 197E finds motions (i.e., translational,rotational), conformations, and presence of objects within sensoryinformation provided by detection system 90A. The findings of motioncapture and sensory analyzer 197E serve as input of sensed (e.g.,observed) information from the environment with which model refiner 197Fcan update predictive information (e.g., models, model portions, modelattributes, etc.).

A model management module 197 implementation comprises a model refiner197F to update one or more models 197B (or portions thereof) fromsensory information (e.g., images, scans, other sensory-perceptiblephenomenon) and environmental information (i.e., context, noise, etc.);enabling a model analyzer 197I to recognize object, position, motion andattribute information that might be useful in controlling a machine.Model refiner 197F employs an object library 197A to manage objectsincluding one or more models 197B (i.e., of user portions (e.g., hand,face), other control objects (e.g., styli, tools)) or the like (seee.g., model 197B-1, 197B-2 of FIGS. 8-1, 8-2)), model components (i.e.,shapes, 2D model portions that sum to 3D, outlines 194 and/or outlineportions 194A, 194B (i.e., closed curves), attributes 197-5 (e.g.,attach points, neighbors, sizes (e.g., length, width, depth),rigidity/flexibility, torsional rotation, degrees of freedom of motionand others) and so forth) (see e.g., 197B-1-197B-2 of FIGS. 8-1-8-2),useful to define and update models 197B, and model attributes 197-5.While illustrated with reference to a particular implementation in whichmodels, model components and attributes are co-located within a commonobject library 197A, it should be understood that these objects will bemaintained separately in some implementations.

In an implementation, when the control object morphs, conforms, and/ortranslates, motion information reflecting such motion(s) is includedinto the observed information. Points in space can be recomputed basedon the new observation information. The model subcomponents can bescaled, sized, selected, rotated, translated, moved, or otherwisere-ordered to enable portions of the model corresponding to the virtualsurface(s) to conform within the set of points in space.

In an implementation, motion(s) of the control object can be rigidtransformation, in which case, points on the virtual surface(s) remainat the same distance(s) from one another through the motion. Motion(s)can be non-rigid transformations, in which points on the virtualsurface(s) can vary in distance(s) from one another during the motion.In an implementation, observation information can be used to adjust(and/or recomputed) predictive information thereby enabling “tracking”the control object. In implementations, control object can be tracked bydetermining whether a rigid transformation or a non-rigid transformationoccurs. In an implementation, when a rigid transformation occurs, atransformation matrix is applied to each point of the model uniformly.Otherwise, when a non-rigid transformation occurs, an error indicationcan be determined, and an error minimization technique such as describedherein above can be applied. In an implementation, rigid transformationsand/or non-rigid transformations can be composed. One examplecomposition implementation includes applying a rigid transformation topredictive information. Then an error indication can be determined, andan error minimization technique such as described herein above can beapplied. In an implementation, determining a transformation can includecalculating a rotation matrix that provides a reduced RMSD (root meansquared deviation) between two paired sets of points. One implementationcan include using Kabsch Algorithm to produce a rotation matrix. In animplementation and by way of example, one or more force lines can bedetermined from one or more portions of a virtual surface.

FIG. 21 illustrates prediction information including a model 197B-1 of acontrol object (e.g., FIG. 17: 99) constructed from one or more modelsubcomponents 197-2, 197-3 selected and/or configured to represent atleast a portion of a surface of control object 99, a virtual surfaceportion 194 and one or more attributes 197-5. Other components can beincluded in prediction information 197B-1 not shown in FIG. 21 forclarity sake. In an implementation, the model subcomponents 197-2, 197-3can be selected from a set of radial solids, which can reflect at leasta portion of a control object 99 in terms of one or more of structure,motion characteristics, conformational characteristics, other types ofcharacteristics of control object 99, and/or combinations thereof. Inone implementation, radial solids include a contour and a surfacedefined by a set of points having a fixed distance from the closestcorresponding point on the contour. Another radial solid implementationincludes a set of points normal to points on a contour and a fixeddistance therefrom. In an implementation, computational technique(s) fordefining the radial solid include finding a closest point on the contourand the arbitrary point, then projecting outward the length of theradius of the solid. In an implementation, such projection can be avector normal to the contour at the closest point. An example radialsolid (e.g., 197-3) includes a “capsuloid”, i.e., a capsule shaped solidincluding a cylindrical body and semi-spherical ends. Another type ofradial solid (e.g., 197-2) includes a sphere. Other types of radialsolids can be identified based on the foregoing teachings.

One or more attributes 197-5 can define characteristics of a modelsubcomponent 197-3. Attributes can include e.g., attach points,neighbors, sizes (e.g., length, width, depth), rigidity, flexibility,torsion, zero or more degrees of freedom of motion with respect to oneor more defined points, which can include endpoints for example, andother attributes defining a salient characteristic or property of aportion of control object 99 being modeled by predictive information197B-1. In an implementation, predictive information about the controlobject can include a model of the control object together withattributes defining the model and values of those attributes.

In an implementation, observation information including observation ofthe control object can be compared against the model at one or more ofperiodically, randomly or substantially continuously (i.e., in realtime). Observational information can include without limitation observedvalues of attributes of the control object corresponding to theattributes of one or more model subcomponents in the predictiveinformation for the control object. In an implementation, comparison ofthe model with the observation information provides an error indication.In an implementation, an error indication can be computed by determininga closest distance determined between a first point A belonging to a setof points defining the virtual surface 194 and a second point Bbelonging to a model subcomponent 197-2 determined to be correspondingto the first point (e.g., nearest to the first point for example). In animplementation, the error indication can be applied to the predictiveinformation to correct the model to more closely conform to theobservation information. In an implementation, error indication can beapplied to the predictive information repeatedly until the errorindication falls below a threshold, a measure of conformance with theobservation information rises above a threshold, or a fixed or variablenumber of times, or a fixed or variable number of times per time period,or combinations thereof.

In an implementation and with reference to FIG. 17 and FIG. 22, updatingpredictive information to observed information comprises selecting oneor more sets of points (e.g., FIG. 22:193A, 193B, 193C, 193D) in spacesurrounding or bounding the control object 197B-2 within a field of viewof one or more image capture device(s). As shown by FIG. 22, points193A, 193B, 193C, 193D can be determined using one or more sets of lines195A, 195B, 195C, and 195D originating at vantage point(s) (e.g., FIG.17: 190-1, 190-2) associated with the image capture device(s) (e.g.,FIG. 17: 190A-1, 190A-2) and determining therefrom one or moreintersection point(s) defining a bounding region 189A (i.e., regionformed by lines FIG. 22: 195A, 195B, 195C, and 195D) surrounding across-section of the control object. The centerline of the boundingregion can be found by identifying diagonal line segments 2212, 2214that connect the opposite corners of the bounded region, identifying themidpoints 2216, 2218 of these line segments, and identifying the linesegment 2220 joining the midpoints 2216, 2218 as the centerline. (Asecond centerline 2234 for second unbounded region 189B is found fromextension of centerline 2220 beyond line 2232 into region 189B. Bothcenterlines can factor into a solution and one is typically discarded asbeyond range of interest.) The bounding region can be used to define avirtual surface (FIG. 22: 194) to which model subcomponents 197-1,197-2, 197-3, and 197-4 can be compared. The virtual surface 194 caninclude a visible portion 194A and a non-visible “inferred” portion194B. Virtual surfaces 194 can include straight portions and/or curvedsurface portions of one or more virtual solids (i.e., model portions)determined by model refiner 197F.

For example and according to one implementation illustrated by FIG. 22,model refiner 197F determines to model subcomponent 197-1 of an objectportion (happens to be a finger) using a virtual solid, an ellipse inthis illustration, or any of a variety of 3D shapes (e.g., ellipsoid,sphere, or custom shape) and/or 2D slice(s) that are added together toform a 3D volume. Accordingly, beginning with generalized equations foran ellipse (1) with (x, y) being the coordinates of a point on theellipse, (x_(C), y_(C)) the center, a and b the axes, and 0 the rotationangle. The coefficients C₁, C₂ and C₃ are defined in terms of theseparameters, as shown:

$\quad\begin{matrix}{{{{C_{1}x^{2}} + {C_{2}{xy}} + {C_{3}y^{2}} - {\left( {{2C_{1}x_{c}} + {C_{2}y_{c}}} \right)x} - {\left( {{2C_{3}y_{c}} + {C_{2}x_{c}}} \right)y} + \left( {{C_{1}x_{c}^{2}} + {C_{2}x_{c}y_{c}} + {C_{3}y_{c}^{2}} - 1} \right)} = 0}\begin{matrix}{\mspace{76mu}{C_{1} = {\frac{\cos^{2}\theta}{a^{2}} + \frac{\sin^{2}\theta}{b^{2}}}}} \\{\mspace{76mu}{C_{2} = {{- 2}{{\cos{\theta sin\theta}}\left( {\frac{1}{a^{2}} - \frac{1}{b^{2}}} \right)}}}} \\{\mspace{76mu}{C_{3} = {\frac{\sin^{2}\theta}{a^{2}} + \frac{\cos^{2}\theta}{b^{2}}}}}\end{matrix}} & (5)\end{matrix}$

The ellipse equation (5) is solved for 0, subject to the constraintsthat: (5) (x_(C), Y_(C)) must lie on the centerline determined from thefour tangents 195A, 195B, 195C, and 195D (i.e., centerline 2220 of FIG.22); and (6) a is fixed at the assumed value a₀. The ellipse equationcan either be solved for 0 analytically or solved using an iterativenumerical solver (e.g., a Newtonian solver as is known in the art). Ananalytic solution can be obtained by writing an equation for thedistances to the four tangent lines given a y_(C) position, then solvingfor the value of y_(C) that corresponds to the desired radius parametera=a₀. Accordingly, equations (6) for four tangent lines in the x-y plane(of the slice), in which coefficients A_(i), B_(i) and D_(i) (for i=1 to4) are determined from the tangent lines 195A, 195B, 195C, and 195Didentified in an image slice as described above.

$\begin{matrix}{{{{A_{1}x} + {B_{1}y} + D_{1}} = 0}{{{A_{2}x} + {B_{2}y} + D_{2}} = 0}{{{A_{3}x} + {B_{3}y} + D_{3}} = 0}{{{A_{4}x} + {B_{4}y} + D_{4}} = 0}} & (6)\end{matrix}$

Four column vectors r₁₂, r₂₃, r₁₄ and r₂₄ are obtained from thecoefficients A_(i), B_(i) and D_(i) of equations (6) according toequations (7), in which the “\” operator denotes matrix left division,which is defined for a square matrix M and a column vector v such thatM\v=r, where r is the column vector that satisfies Mr=v:

$\begin{matrix}{\quad{r_{13} = {{\begin{bmatrix}A_{1} & B_{1} \\A_{3} & B_{3}\end{bmatrix}\backslash\;\begin{bmatrix}{- D_{1}} \\{- D_{3}}\end{bmatrix}}{\quad{r_{23} = {{\begin{bmatrix}A_{2} & B_{2} \\A_{3} & B_{3}\end{bmatrix}\backslash\;\begin{bmatrix}{- D_{21}} \\{- D_{3}}\end{bmatrix}}{\quad{r_{14} = {{\begin{bmatrix}A_{1} & B_{1} \\A_{4} & B_{4}\end{bmatrix}\backslash\;\begin{bmatrix}{- D_{1}} \\{- D_{4}}\end{bmatrix}}{\quad{r_{24} = {\begin{bmatrix}A_{2} & B_{2} \\A_{4} & B_{4}\end{bmatrix}\backslash\;\begin{bmatrix}{- D_{2}} \\{- D_{4}}\end{bmatrix}}}}}}}}}}}}} & (7)\end{matrix}$

Four component vectors G and H are defined in equations (8) from thevectors of tangent coefficients A, B and D and scalar quantities p andq, which are defined using the column vectors r₁₂, r₂₃, r₁₄ and r₂₄ fromequations (7).c1=(r ₁₃ +r ₂₄)/2c ₂=(r ₁₄ +r ₂₃)/2δ1=c2₁ −c1₁δ2=c2₂ −c1₂p=δ1/δ2q=c1₁ −c1₂ *pG=Ap+BH=Aq+D  (8)

Six scalar quantities V_(A2), V_(AB), V_(B2), W_(A2), W_(AB), and W_(B2)are defined by equation (9) in terms of the components of vectors G andH of equation (8).

$\quad\begin{matrix}{{v = {\left\lbrack {\begin{matrix}G_{2}^{2} \\\left( {G_{2}H_{2}} \right)^{2} \\H_{2}^{2}\end{matrix}\begin{matrix}G_{3}^{2} \\\left( {G_{3}H_{3}} \right)^{2} \\H_{3}^{2}\end{matrix}\begin{matrix}G_{4}^{2} \\\left( {G_{4}H_{4}} \right)^{2} \\H_{4}^{2}\end{matrix}} \right\rbrack{\ddots\begin{bmatrix}0 \\0 \\1\end{bmatrix}}}}{w = {\left\lbrack {\begin{matrix}G_{2}^{2} \\\left( {G_{2}H_{2}} \right)^{2} \\H_{2}^{2}\end{matrix}\begin{matrix}G_{3}^{2} \\\left( {G_{3}H_{3}} \right)^{2} \\H_{3}^{2}\end{matrix}\begin{matrix}G_{4}^{2} \\\left( {G_{4}H_{4}} \right)^{2} \\H_{4}^{2}\end{matrix}} \right\rbrack{\ddots\begin{bmatrix}0 \\1 \\0\end{bmatrix}}}}{v_{A2} = {\left( {v_{1}A_{1}} \right)^{2} + \left( {v_{2}A_{2}} \right)^{2} + \left( {v_{3}A_{3}} \right)^{2}}}{v_{AB} = {\left( {v_{1}A_{1}B_{1}} \right)^{2} + \left( {v_{2}A_{2}B_{2}} \right)^{2} + \left( {v_{3}A_{3}B_{3}} \right)^{2}}}{v_{B2} = {\left( {v_{1}B_{1}} \right)^{2} + \left( {v_{2}B_{2}} \right)^{2} + \left( {v_{3}B_{3}} \right)^{2}}}{w_{A2} = {\left( {w_{1}A_{1}} \right)^{2} + \left( {w_{2}A_{2}} \right)^{2} + \left( {w_{3}A_{3}} \right)^{2}}}{w_{AB} = {\left( {w_{1}A_{1}B_{1}} \right)^{2} + \left( {w_{2}A_{2}B_{2}} \right)^{2} + \left( {w_{3}A_{3}B_{3}} \right)^{2}}}{w_{B2} = {\left( {w_{1}B_{1}} \right)^{2} + \left( {w_{2}B_{2}} \right)^{2} + \left( {w_{3}B_{3}} \right)^{2}}}} & (9)\end{matrix}$

Using the parameters defined in equations (5)-(9), solving for 0 isaccomplished by solving the eighth-degree polynomial equation (6) for t,where the coefficients Q_(i) (for i=0 to 8) are defined as shown inequations (11)-(119).0=Q ₈ t ⁸ +Q ₇ t ⁷ +Q ₆ t ⁶ +Q ₅ t ⁵ +Q ₄ t ⁴ +Q ₃ t ³ +Q ₂ t ² +Q ₁ t+Q₀  (10)

The parameters A₁, B₁, G₁, H₁, V_(A2), V_(AB), V_(B2), W_(A2), W_(AB),and W_(B2) used in equations (11)-(15) are defined as shown in equations(5)-(8). The parameter n is the assumed semi-major axis (in other words,a₀). Once the real roots t are known, the possible values of 0 aredefined as 0=atan(t).Q ₈=4A ₁ ² n ² v ² _(B2)+4v _(B2) B ₁ ²(1−n ² v _(A2))−(G ₁(1−n ² v_(A2))w _(B2) +n ² v _(B2) w _(A2)+2H ₁ v _(B2))²  (11)Q ₇=−(2(2n ² v _(AB) w _(A2)+4H ₁ v _(AB)+2G ₁ n ² v _(AB) w _(B2)+2G₁(1−n ² v _(A2))w _(AB)))(G ₁(1−n ² v _(A2))w _(B2) +n ² v _(B2) w_(A2)+2H ₁ v _(B2))−8A ₁ B ₁ n ² v _(B2) ²+16A ₁ ² n ² v _(AB) v_(B2)+(4(2A ₁ B ₁(1−n ² v _(A2))+2B ₁ ² n ² v _(AB)))v _(B2)+8B ₁ ²(1−n² v _(A2))v _(AB)  (12)Q ₆=−(2(2H ₁ v _(B2)+2H ₁ v _(A2) +n ² v _(A2) w _(A2) +n ² v _(B2)(−2w_(AB) +w _(B2))+G ₁(n ² v _(B2)+1)w _(B2)+4G ₁ n ² v _(AB) w _(AB) +G₁(1−n ² v _(A2))v _(A2)))x(G ₁(1−n ² v _(A2))w _(B2) +n ² v _(B2) w_(A2)+2H ₁ v _(B2))−(2n ² v _(AB) w _(A2)+4H ₁ v _(AB)+2G ₁ n ² v _(AB)w _(B2)+2G ₁(1−n ² v _(A2))w _(AB))²+4B ₁ ² n ² v _(B2) ²−32A ₁ B ₁ n ²v _(AB) v _(B2)+4A ₁ ² n ₂(2v _(A2) v _(B2)+4v _(AB) ²)+4A ₁ ² n ² v_(B2) ²+(A(A ₁ ²(1−n ² v _(A2))+4A ₁ B ₁ n ² v _(AB) +B ₁ ²(−n ² v_(B2)+1)+B ₁ ²(1−n ² v _(A2))))v _(B2)+(8(2A ₁ B ₁(1−n ² v _(A2))+2B ₁ ²n ² v _(AB)))v _(AB)+4B ₁ ²(1−n ² v _(A2))v _(A2)  (13)Q ₅=−(2(4H ₁ v _(AB)+2G ₁(−n ² v _(B2)+1)w _(AB)+2G ₁ n ² v _(AB) v_(A2)+2n ² v _(A)(−2w _(AB) +w _(B2))))(G ₁(1−n ² v _(A2))w _(B2) +n ² v_(B2) w _(A2)+2H ₁ v _(B2))−(2(2H ₁ v _(B2)+2H ₁ v _(A2) +n ² v _(A2) w_(A2) +n ^(n) ₂ v _(B2)(−2w _(AB) +w _(B2))+G ₁(−n ² v _(B2)+1)w_(B2)+4G ₁ n ² v _(AB) w _(AB) +G1(1−n ² v _(A2))v _(A2)))x(2n ² v _(AB)w _(A2)+4H ₁ v _(AB)+2G ₁ n ² v _(AB) w _(B2)+2G ₁(1−n ² v _(A2))w_(AB))+16B ₁ ² n ² v _(AB) v _(B2)−6A ₁ B ₁ n ²(2v _(A2) v _(B2)+16A ₁ ²n ² _(A2) v ^(AB)−8A ₁ B ₁ n ² v _(B2) ²+16A ₁ ² n ² v _(AB) v_(B2)+(4(2A ₁ ² n ² v _(AB)+2A ₁ B ₁(−n ² v _(B2)+1)+2A ₁ B ₁(1−n ² v_(A2))+2B ₁ ² n ² v _(AB)))v _(B2)+(8(A ₁ ²(1−n ² v _(A2))+4A ₁ B ₁ n ²v _(AB) +B ₁ n ² v _(AB) +B ₁ ²(−n ² v _(B2)+1)+B ₁ ²(1−n ² v _(A2))))v_(AB)+(4(2A ₁ B ₁(1−n ² v _(A2))+2B ₁ ² n ² v _(AB)))v _(A2)  (14)Q ₄=(4(A ₁ ²(−n ² v _(B2))+A ₁ ²(1−n ² v _(B2))+A ₁ ²(1−n ² v _(A2))+4A₁ B ₁ n ² v _(AB) +B ₁ ²(−n ² v _(B2)+1)))v _(B2)+(8(2A ₁ ² n ² v_(AB)+2A ₁ B ₁(−n ² v _(B2)+1)+2A ₁ B ₁(1−n ² v _(A2))+2B ₁ ² n ² v_(AB)))v _(AB)+(4(A ₁ ²(1−n ² v _(A2))+4A ₁ B ₁ n ² v _(AB) +B ₁ ²(−n ²v _(B2)+1)+B ₁ ²(1−n ² v _(A2))))v _(v) ^(A2)+4B ₁ ² n ²(2v _(A2) v_(B2)+4v _(AB) ²)−32A ₁ B ₁ n ² v _(A2) v _(AB)+4A ₁ ² n ² v _(A2) ²+4B₁ ² n ² v _(B2) ²−32A ₁ B ₁ n ² v _(AB) v _(B2)+4A ₁ ² n ²(2v _(A2) v_(B2)+4v _(AB) ²)−(2(G ₁(−n ² v _(B2)+1)v _(A2) +n ² v _(A2)(−2w _(AB)+w _(B2))+2H ₁ v _(A2)))(G ₂(1−n ² v _(A2))w _(B2) +n ² v _(B2) w_(A2)+2H ₁ v _(B2))−(2(4H ₁ v _(AB)+2H ₁(−n ² v _(B2)+1)w _(AB)+2G ₁ n ²n ² v _(AB) v _(A2)+2n ² v _(AB)(−2w _(AB) +w _(B2))))x(2n ² v _(AB) w_(A2)+4H ₁ v _(AB)+2G ₁ n ² v _(AB) w _(B2)+2G ₁(1−n ² v _(A2))w_(AB))−(2H ₁ v _(B2)+2H ₁ v _(A2) +n ² v _(A2) w _(A2) +n ² v _(B2)(−2w_(AB) +w _(B2))+G ₁(−n ² v _(B2)+1)w _(B2)+4G ₁ n ² v _(AB) w _(AB) +G₁(1−n ² v _(A2))v _(A2))²  (15)Q ₃=−(2(G ₁(−n ² v _(B2)+1)v _(A2) +n ² v _(A2)(−2w _(AB) +w _(B2))+2H ₁v _(A2)))(2n ² v _(AB) w _(A2)+4H ₁ v _(AB)+2G ₁ n ² v _(AB) w _(B2)+2G₁(1−n ² v _(A2))w _(AB))−(2(4H ₁ v _(AB)+2G ₁(−n ² v _(B2)+1)w _(AB)+2G₁ n ² v _(AB) v _(A2)+2n ² v _(AB)(−2w _(AB) +w _(B2))))x(2H ₁ v_(B2)+2H ₁ v _(A2) +n ² v _(A2) w _(A2) +n ² v _(B2)(−2w _(AB) +w_(B2))+G ₁(−n ² v _(B2)+1)w _(B2)+4G ₁ n ² v _(AB) w _(AB) +G ₁(1−n ² v_(A2))v _(A2))+16B ₁ ² n ² v _(A2) v _(AB)−8A ₁ B ₁ n ² v _(A2) ²+16B ₁² n ² v _(AB) v _(B2)−8A ₁ B ₁ n ²(2v _(A2) v _(B2)+4v _(AB) ²)+16A ₁ ²n ² v _(A2) v _(AB)+(4(2A ₁ ² n ² v _(AB)+2A ₁ B ₁(−n ² v _(B2)+1)))v_(B2)+(6(A ₁ ²(−n ² v _(B2)+1)+A ₁ ²(1−n ² v _(A2))+4A ₁ B ₁ n ² v _(AB)+B ₁(−² n ² v _(B2)+1)))v _(AB)+(4(2A ₁ ² n ² v _(AB)+2A ₁ B ₁(−n ² v_(B2)+1)+2A ₁ B ₁(1−n ² v _(A2))+2B ₁ ² n ² v _(AB)))v _(A2)  (16)Q ₂=4A ₁ ²(−n ² v _(B2)+1)v _(B2)+(6(2A ₁ ² n ² v _(AB)+2A ₁ B ₁(−n ² v_(B2)+1)))v _(AB)+(4(A ₁ ²(−n ² v _(B2)+1)+A ₁ ²(1−n ² v _(A2))+4A ₁ B ₁n ² v _(AB) +B ₁ ²(−n ² v _(B2)+1)))v _(A2)+4B ₁ ² n ² v _(A2) ²+4B ₁ ²n ²(2v _(A2) v _(B2)+4v _(AB) ²)−32A ₁ B ₁ n ² v _(A2) v _(AB)+4A ₁ ² n² v _(A2) ²−(2(G ₁(−n ² v _(B2)+1)v _(A2) +n ² v _(A2)(−2w _(AB) +w_(B2))+2H ₁ v _(A2)))x(2H ₁ v _(B2)+2H ₁ v _(A2) +n ² v _(A2) w _(A2) +n² v _(B2)(−2w _(AB) +w _(B2))+G ₁(−n ² v _(B2)+1)w _(B2)+4G ₁ n ² v_(AB) w _(AB) +G ₁(1−n ² v _(A2))v _(A2))−(4H ₁ v _(AB)+2G ₁(−n ² v_(B2)+1)w _(AB)+2G ₁ n ² v _(AB) v _(A2)+2n ² v _(AB)(−2w _(AB) +w_(B2)))²  (17)Q ₁=8A ₁ ²(−n ² v _(B2)+1)v _(AB)+(4(2A ₁ ² n ² v _(AB)+2A ₁ B ₁(−n ² v_(B2)+1)))v _(A2)+16B ₁ ² n ² v _(AB)−8A ₁ B ₁ n ² x ² _(A2)=(2(G ₁(−n ²v _(B2)+1)v _(A2) +n ² v _(A2)(−2w _(AB) +w _(B2))+2H ₁ v _(A2)))(4H ₁ v_(AB)+2G ₁(−n ² v _(B2)+1)w _(AB)+2G ₁ n ² v _(AB) v _(A2)+2n ² v_(AB)(−2w _(AB) +w _(B2)))  (18)Q ₀=4A ₁ ²(−n ² v _(B2)+1)v _(A2)−(G ₁(−n ² v _(B2)+1)v _(A2) +n ² v_(A2)(−2w _(AB) +w _(B2))+2H ₁ v _(A2))²+4B ₁ ² n ² v ² _(A2)  (19)

In this exemplary implementation, equations (10)-(11) have at most threereal roots; thus, for any four tangent lines, there are at most threepossible ellipses that are tangent to all four lines and that satisfythe a=a₀ constraint. (In some instances, there may be fewer than threereal roots.) For each real root θ, the corresponding values of (x_(C),y_(C)) and b can be readily determined. Depending on the particularinputs, zero or more solutions will be obtained; for example, in someinstances, three solutions can be obtained for a typical configurationof tangents. Each solution is completely characterized by the parameters{θ, a=a₀, b, (x_(C), y_(C))}. Alternatively, or additionally, a modelbuilder 197C and model updater 197D provide functionality to define,build and/or customize model(s) 197B using one or more components inobject library 197A. Once built, model refiner 197F updates and refinesthe model, bringing the predictive information of the model in line withobserved information from the detection system 90A.

The model subcomponents 197-1, 197-2, 197-3, and 197-4 can be scaled,sized, selected, rotated, translated, moved, or otherwise re-ordered toenable portions of the model corresponding to the virtual surface(s) toconform within the points 193A, 193B, 193C, 193D in space. Model refiner197F employs a variation detector 197G to substantially continuouslydetermine differences between sensed information and predictiveinformation and provide to model refiner 197F a variance useful toadjust the model 197B accordingly. Variation detector 197G and modelrefiner 197F are further enabled to correlate among model portions topreserve continuity with characteristic information of a correspondingobject being modeled, continuity in motion, and/or continuity indeformation, conformation and/or torsional rotations.

An environmental filter 197H reduces extraneous noise in sensedinformation received from the detection system 90A using environmentalinformation to eliminate extraneous elements from the sensoryinformation. Environmental filter 197H employs contrast enhancement,subtraction of a difference image from an image, software filtering, andbackground subtraction (using background information provided by objectsof interest determiner 198H (see below) to enable model refiner 197F tobuild, refine, manage and maintain model(s) 197B of objects of interestfrom which control inputs can be determined.

A model analyzer 197I determines that a reconstructed shape of a sensedobject portion matches an object model in an object library; andinterprets the reconstructed shape (and/or variations thereon) as userinput. Model analyzer 197I provides output in the form of object,position, motion and attribute information to an interaction system 90C.

Again with reference to FIG. 20, an interaction system 90C includes aninteraction interpretation module 198 that provides functionality torecognize command and other information from object, position, motionand attribute information obtained from variation system 90B. Aninteraction interpretation module 198 implementation comprises arecognition engine 198F to recognize command information such as commandinputs (i.e., gestures and/or other command inputs (e.g., speech,etc.)), related information (i.e., biometrics), environmentalinformation (i.e., context, noise, etc.) and other informationdiscernable from the object, position, motion and attribute informationthat might be useful in controlling a machine. Recognition engine 198Femploys gesture properties 198A (e.g., path, velocity, acceleration,etc.), control objects determined from the object, position, motion andattribute information by an objects of interest determiner 198H andoptionally one or more virtual constructs 198B (see e.g., FIGS. 23A,23B: 198B-1, 198B-2) to recognize variations in control object presenceor motion indicating command information, related information,environmental information and other information discernable from theobject, position, motion and attribute information that might be usefulin controlling a machine. With reference to FIGS. 23A, 23B, virtualconstruct 198B-1, 198B-2 implement an engagement target with which acontrol object 99 interacts—enabling MSCS 189 to discern variations incontrol object (i.e., motions into, out of or relative to virtualconstruct 198B) as indicating control or other useful information. Againwith reference to FIG. 20, a gesture trainer 198C and gesture propertiesextractor 198D provide functionality to define, build and/or customizegesture properties 198A.

A context determiner 198G and object of interest determiner 198H providefunctionality to determine from the object, position, motion andattribute information objects of interest (e.g., control objects, orother objects to be modeled and analyzed), objects not of interest(e.g., background) based upon a detected context. For example, when thecontext is determined to be an identification context, a human face willbe determined to be an object of interest to the system and will bedetermined to be a control object. On the other hand, when the contextis determined to be a fingertip control context, the finger tips will bedetermined to be object(s) of interest and will be determined to be acontrol objects whereas the user's face will be determined not to be anobject of interest (i.e., background). Further, when the context isdetermined to be a styli (or other tool) held in the fingers of theuser, the tool tip will be determined to be object of interest and acontrol object whereas the user's fingertips might be determined not tobe objects of interest (i.e., background). Background objects can beincluded in the environmental information provided to environmentalfilter 197H of model management module 197.

A virtual environment manager 198E provides creation, selection,modification and de-selection of one or more virtual constructs 198B(see FIGS. 23A, 23B). In some implementations, virtual constructs (e.g.,a virtual object defined in space; such that variations in real objectsrelative to the virtual construct, when detected, can be interpreted forcontrol or other purposes (see FIGS. 23A, 23B)) are used to determinevariations (i.e., virtual “contact” with the virtual construct, breakingof virtual contact, motion relative to a construct portion, etc.) to beinterpreted as engagements, dis-engagements, motions relative to theconstruct(s), and so forth, enabling the system to interpret pinches,pokes and grabs, and so forth. Interaction interpretation module 198provides as output the command information, related information andother information discernable from the object, position, motion andattribute information that might be useful in controlling a machine fromrecognition engine 198F to an application control system 90D.

In an implementation, predictive information can include collisioninformation concerning two or more capsoloids. By means of illustration,several possible fits of predicted information to observed informationcan be removed from consideration based upon a determination that thesepotential solutions would result in collisions of capsoloids. In animplementation, a relationship between neighboring capsoloids, eachhaving one or more attributes (e.g., determined minima and/or maxima ofintersection angles between capsoloids) can be determined. In animplementation, determining a relationship between a first capsoloidhaving a first set of attributes and a second capsoloid having a secondset of attributes includes detecting and resolving conflicts betweenfirst attribute and second attributes. For example, a conflict caninclude a capsoloid having one type of angle value with a neighborhaving a second type of angle value incompatible with the first type ofangle value. Attempts to attach a capsoloid with a neighboring capsoloidhaving attributes such that the combination will exceed what is allowedin the observed—or to pair incompatible angles, lengths, shapes, orother such attributes—can be removed from the predicted informationwithout further consideration.

In an implementation, predictive information can be artificiallyconstrained to capsoloids positioned in a subset of the observedinformation—thereby enabling creation of a “lean model”. For example, asillustrated in FIG. 21, capsoloid 197-3 could be used to denote theportion of the observed without addition of capsoloids 197-2. In a yetfurther implementation, connections can be made using artificialconstructs to link together capsoloids of a lean model. In anotherimplementation, the predictive information can be constrained to asubset of topological information about the observed informationrepresenting the control object to form a lean model.

In an implementation, a lean model can be associated with a fullpredictive model. The lean model (or topological information, orproperties described above) can be extracted from the predictive modelto form a constraint. Then, the constraint can be imposed on thepredictive information thereby enabling the predictive information to beconstrained in one or more of behavior, shape, total (system) energy,structure, orientation, compression, shear, torsion, other properties,and/or combinations thereof.

In an implementation, the observed can include components reflectingportions of the control object which are occluded from view of thedevice (“occlusions” or “occluded components”). In one implementation,the predictive information can be “fit” to the observed as describedherein above with the additional constraint(s) that some total propertyof the predictive information (e.g., potential energy) be minimized ormaximized (or driven to lower or higher value(s) through iteration orsolution). Properties can be derived from nature, properties of thecontrol object being viewed, others, and/or combinations thereof. Inanother implementation, as shown by FIGS. 16A and 16B, a deformation ofthe predictive information subcomponents 1602 and 1612 can be allowedsubject to an overall permitted value of compression, deformation,flexibility, others, and/or combinations thereof.

In an implementation, a “friction constraint” is applied on the model197B-1. For example, if fingers of a hand being modeled are closetogether (in position or orientation), corresponding portions of themodel will have more “friction”. The more friction a model subcomponenthas in the model, the less the subcomponent moves in response to newobserved information. Accordingly the model is enabled to mimic the wayportions of the hand that are physically close together move together,and move less overall.

An environmental filter 197H reduces extraneous noise in sensedinformation received from the detection system 90A using environmentalinformation to eliminate extraneous elements from the sensoryinformation. Environmental filter 197H employs contrast enhancement,subtraction of a difference image from an image, software filtering, andbackground subtraction (using background information provided by objectsof interest determiner 198H (see below) to enable model refiner 197F tobuild, refine, manage and maintain model(s) 197B of objects of interestfrom which control inputs can be determined.

A model analyzer 197I determines that a reconstructed shape of a sensedobject portion matches an object model in an object library; andinterprets the reconstructed shape (and/or variations thereon) as userinput. Model analyzer 197I provides output in the form of object,position, motion and attribute information to an interaction system 90C.

Again with reference to FIG. 20, an interaction system 90C includes aninteraction interpretation module 198 that provides functionality torecognize command and other information from object, position, motionand attribute information obtained from variation system 90B. Aninteraction interpretation module 198 implementation comprises arecognition engine 198F to recognize command information such as commandinputs (i.e., gestures and/or other command inputs (e.g., speech,etc.)), related information (i.e., biometrics), environmentalinformation (i.e., context, noise, etc.) and other informationdiscernable from the object, position, motion and attribute informationthat might be useful in controlling a machine. Recognition engine 198Femploys gesture properties 198A (e.g., path, velocity, acceleration,etc.), control objects determined from the object, position, motion andattribute information by an objects of interest determiner 198H andoptionally one or more virtual constructs 198B (see e.g., FIGS. 23A,23B: 198B-1, 198B-2) to recognize variations in control object presenceor motion indicating command information, related information,environmental information and other information discernable from theobject, position, motion and attribute information that might be usefulin controlling a machine. With reference to FIG. 23A, 23B, virtualconstruct 198B-1, 198B-2 implement an engagement target with which acontrol object 99 interacts—enabling MSCS 189 to discern variations incontrol object (i.e., motions into, out of or relative to virtualconstruct 198B) as indicating control or other useful information. Agesture trainer 198C and gesture properties extractor 198D providefunctionality to define, build and/or customize gesture properties 198A.

A context determiner 198G and object of interest determiner 198H providefunctionality to determine from the object, position, motion andattribute information objects of interest (e.g., control objects, orother objects to be modeled and analyzed), objects not of interest(e.g., background) based upon a detected context. For example, when thecontext is determined to be an identification context, a human face willbe determined to be an object of interest to the system and will bedetermined to be a control object. On the other hand, when the contextis determined to be a fingertip control context, the finger tips will bedetermined to be object(s) of interest and will be determined to be acontrol objects whereas the user's face will be determined not to be anobject of interest (i.e., background). Further, when the context isdetermined to be a styli (or other tool) held in the fingers of theuser, the tool tip will be determined to be object of interest and acontrol object whereas the user's fingertips might be determined not tobe objects of interest (i.e., background). Background objects can beincluded in the environmental information provided to environmentalfilter 197H of model management module 197.

Further with reference to FIG. 20, an application control system 90Dincludes a control module 199 that provides functionality to determineand authorize commands based upon the command and other informationobtained from interaction system 90C.

A control module 199 implementation comprises a command engine 199F todetermine whether to issue command(s) and what command(s) to issue basedupon the command information, related information and other informationdiscernable from the object, position, motion and attribute information,as received from an interaction interpretation module 198. Commandengine 199F employs command/control repository 199A (e.g., applicationcommands, OS commands, commands to MSCS, misc. commands) and relatedinformation indicating context received from the interactioninterpretation module 198 to determine one or more commandscorresponding to the gestures, context, etc. indicated by the commandinformation. For example, engagement gestures can be mapped to one ormore controls, or a control-less screen location, of a presentationdevice associated with a machine under control. Controls can includeimbedded controls (e.g., sliders, buttons, and other control objects inan application), or environmental level controls (e.g., windowingcontrols, scrolls within a window, and other controls affecting thecontrol environment). In implementations, controls may be displayedusing 2D presentations (e.g., a cursor, cross-hairs, icon, graphicalrepresentation of the control object, or other displayable object) ondisplay screens and/or presented in 3D forms using holography,projectors or other mechanisms for creating 3D presentations, or audible(e.g., mapped to sounds, or other mechanisms for conveying audibleinformation) and/or touchable via haptic techniques.

Further, an authorization engine 199G employs biometric profiles 199B(e.g., users, identification information, privileges, etc.) andbiometric information received from the interaction interpretationmodule 198 to determine whether commands and/or controls determined bythe command engine 199F are authorized. A command builder 199C andbiometric profile builder 199D provide functionality to define, buildand/or customize command/control repository 199A and biometric profiles199B.

Selected authorized commands are provided to machine(s) under control(i.e., “client”) via interface layer 196. Commands/controls to thevirtual environment (i.e., interaction control) are provided to virtualenvironment manager 198E. Commands/controls to the emission/detectionsystems (i.e., sensory control) are provided to emission module 91and/or detection module 92 as appropriate.

In various implementations and with reference to FIG. 23A, 23B, aMachine Sensory Controller System 189 provides a virtual touch surface188-1, 198B-1 with which the user can interact. Machine SensoryController System 189 can be embodied as a standalone unit(s) 189-1coupled via an interface (e.g., wired or wireless)), embedded (e.g.,within a machine 189-2, 189-3 or machinery under control) (e.g., FIG.23A: 189-1, 189-2, 189-3, FIG. 23B: 189B) or combinations thereof.

FIG. 24 illustrates an example computing system that can comprise one ormore of the elements shown in FIGS. 16A and 16B. In particular, FIG. 24illustrates an exemplary computing system 2400, such as a PC (or othersuitable “processing” system), that can comprise one or more of the MSCSelements shown in FIGS. 17-20 according to an implementation. Whileother application-specific device/process alternatives might beutilized, such as those already noted, it will be presumed for claritysake that systems 90A-90D elements (FIGS. 17-20) are implemented by oneor more processing systems consistent therewith, unless otherwiseindicated.

As shown, computer system 2400 comprises elements coupled viacommunication channels (e.g. bus 2401) including one or more general orspecial purpose processors 2402, such as a Pentium® or Power PC®,digital signal processor (“DSP”), or other processing. System 2400elements also include one or more input devices 2403 (such as a mouse,keyboard, joystick, microphone, remote control unit, tactile, biometric,non-tactile 2415 or other sensors, and so on), and one or more outputdevices 2404, such as a suitable display, joystick feedback components,speakers, biometric or other actuators, and so on, in accordance with aparticular application.

System 2400 elements also include a computer readable storage mediareader 2405 coupled to a computer readable storage medium 2406, such asa storage/memory device or hard or removable storage/memory media;examples are further indicated separately as storage device 2408 andnon-transitory memory 2409, which can include hard disk variants,floppy/compact disk variants, digital versatile disk (“DVD”) variants,smart cards, read only memory, random access memory, cache memory orothers, in accordance with a particular application (e.g. see datastore(s) 197A, 198A, 199A and 199B of FIG. 20). One or more suitablecommunication devices 2407 can also be included, such as a modem, DSL,infrared, etc. for providing inter-device communication directly or viasuitable private or public networks, such as the Internet. Workingmemory 2409 is further indicated as including an operating system (“OS”)2491, predictive discrepancy determiner 2413 and other programs 2492,such as application programs, mobile code, data, or other informationfor implementing systems 90A-90D elements, which might be stored orloaded therein during use.

System 2400 element implementations can include hardware, software,firmware or a suitable combination. When implemented in software (e.g.as an application program, object, downloadable, servlet, and so on, inwhole or part), a system 900 element can be communicated transitionallyor more persistently from local or remote storage to memory forexecution, or another suitable mechanism can be utilized, and elementscan be implemented in compiled, simulated, interpretive or othersuitable forms. Input, intermediate or resulting data or functionalelements can further reside more transitionally or more persistently ina storage media or memory, (e.g. storage device 2408 or memory 2409) inaccordance with a particular application.

Certain potential interaction determination, virtual object selection,authorization issuances and other aspects enabled by input/outputprocessors and other element implementations disclosed herein can alsobe provided in a manner that enables a high degree of broad or evenglobal applicability; these can also be suitably implemented at a lowerhardware/software layer. Note, however, that aspects of such elementscan also be more closely linked to a particular application type ormachine, or might benefit from the use of mobile code, among otherconsiderations; a more distributed or loosely coupled correspondence ofsuch elements with OS processes might thus be more desirable in suchcases.

Referring to FIG. 25, which illustrates a system for capturing imagedata according to one implementation of the technology disclosed. System2500 is preferably coupled to a wearable device 2501 that can be apersonal head mounted display (HMD) having a goggle form factor such asshown in FIG. 25, a helmet form factor, or can be incorporated into orcoupled with a watch, smartphone, or other type of portable device.

In various implementations, the system and method for capturing 3Dmotion of an object as described herein can be integrated with otherapplications, such as a head-mounted device or a mobile device.Referring again to FIG. 25, a head-mounted device 2501 can include anoptical assembly that displays a surrounding environment or a virtualenvironment to the user; incorporation of the motion-capture system 2500in the head-mounted device 2501 allows the user to interactively controlthe displayed environment. For example, a virtual environment caninclude virtual objects that can be manipulated by the user's handgestures, which are tracked by the motion-capture system 2500. In oneimplementation, the motion-capture system 2500 integrated with thehead-mounted device 2501 detects a position and shape of user's hand andprojects it on the display of the head-mounted device 2500 such that theuser can see her gestures and interactively control the objects in thevirtual environment. This can be applied in, for example, gaming orinternet browsing.

In one embodiment, information about the interaction with a virtualobject can be shared by a first HMD user with a HMD of a second user.For instance, a team of surgeons can collaborate by sharing with eachother virtual incisions to be performed on a patient. In someembodiments, this is achieved by sending to the second user theinformation about the virtual object, including primitive(s) indicatingat least one of a type, size, and/or features and other informationabout the calculation point(s) used to detect the interaction. In otherembodiments, this is achieved by sending to the second user informationabout the predictive model used to track the interaction.

System 2500 includes any number of cameras 2502, 2504 coupled to sensoryprocessing system 2506. Cameras 2502, 2504 can be any type of camera,including cameras sensitive across the visible spectrum or with enhancedsensitivity to a confined wavelength band (e.g., the infrared (IR) orultraviolet bands); more generally, the term “camera” herein refers toany device (or combination of devices) capable of capturing an image ofan object and representing that image in the form of digital data. Forexample, line sensors or line cameras rather than conventional devicesthat capture a two-dimensional (2D) image can be employed. The term“light” is used generally to connote any electromagnetic radiation,which may or may not be within the visible spectrum, and may bebroadband (e.g., white light) or narrowband (e.g., a single wavelengthor narrow band of wavelengths).

Cameras 2502, 2504 are preferably capable of capturing video images(i.e., successive image frames at a constant rate of at least 15 framesper second); although no particular frame rate is required. Thecapabilities of cameras 2502, 2504 are not critical to the technologydisclosed, and the cameras can vary as to frame rate, image resolution(e.g., pixels per image), color or intensity resolution (e.g., number ofbits of intensity data per pixel), focal length of lenses, depth offield, etc. In general, for a particular application, any camerascapable of focusing on objects within a spatial volume of interest canbe used. For instance, to capture motion of the hand of an otherwisestationary person, the volume of interest might be defined as a cubeapproximately one meter on a side.

As shown, cameras 2502, 2504 can be oriented toward portions 2513 of aregion of interest 2512 by motion of the device 2501, in order to view avirtually rendered or virtually augmented view of the region of interest2512 that can include a variety of virtual objects 2516 as well ascontain an object of interest 2514 (in this example, one or more hands)moves within the region of interest 2512. One or more sensors 2508, 2510capture motions of the device 2501. In some implementations, one or morelight sources 2515, 2517 are arranged to illuminate the region ofinterest 2512. In some implementations, one or more of the cameras 2502,2504 are disposed opposite the motion to be detected, e.g., where thehand 2514 is expected to move. This is an optimal location because theamount of information recorded about the hand is proportional to thenumber of pixels it occupies in the camera images, and the hand willoccupy more pixels when the camera's angle with respect to the hand's“pointing direction” is as close to perpendicular as possible. Sensoryprocessing system 2506, which can be, e.g., a computer system, cancontrol the operation of cameras 2502, 2504 to capture images of theregion of interest 2512 and sensors 2508, 2510 to capture motions of thedevice 2501. Information from sensors 2508, 2510 can be applied tomodels of images taken by cameras 2502, 2504 to cancel out the effectsof motions of the device 2501, providing greater accuracy to the virtualexperience rendered by device 2501. Based on the captured images andmotions of the device 2501, sensory processing system 2506 determinesthe position and/or motion of object 2514.

For example, as an action in determining the motion of object 2514,sensory processing system 2506 can determine which pixels of variousimages captured by cameras 2502, 2504 contain portions of object 2514.In some implementations, any pixel in an image can be classified as an“object” pixel or a “background” pixel depending on whether that pixelcontains a portion of object 2514 or not. Object pixels can thus bereadily distinguished from background pixels based on brightness.Further, edges of the object can also be readily detected based ondifferences in brightness between adjacent pixels, allowing the positionof the object within each image to be determined. In someimplementations, the silhouettes of an object are extracted from one ormore images of the object that reveal information about the object asseen from different vantage points. While silhouettes can be obtainedusing a number of different techniques, in some implementations, thesilhouettes are obtained by using cameras to capture images of theobject and analyzing the images to detect object edges. Correlatingobject positions between images from cameras 2502, 2504 and cancellingout captured motions of the device 2501 from sensors 2508, 2510 allowssensory processing system 2506 to determine the location in 3D space ofobject 2514, and analyzing sequences of images allows sensory processingsystem 2506 to reconstruct 3D motion of object 2514 using conventionalmotion algorithms or other techniques. See, e.g., U.S. patentapplication Ser. No. 13/414,485 (filed on Mar. 7, 2012) and U.S.Provisional Patent Application Nos. 61/724,091 (filed on Nov. 8, 2012)and 61/587,554 (filed on Jan. 7, 2012), the entire disclosures of whichare hereby incorporated by reference.

Presentation interface 2520 employs projection techniques in conjunctionwith the sensory based tracking in order to present virtual (orvirtualized real) objects (visual, audio, haptic, and so forth) createdby applications loadable to, or in cooperative implementation with, thedevice 2501 to provide a user of the device with a personal virtualexperience. Projection can include an image or other visualrepresentation of an object.

One implementation uses motion sensors and/or other types of sensorscoupled to a motion-capture system to monitor motions within a realenvironment. A virtual object integrated into an augmented rendering ofa real environment can be projected to a user of a portable device 101.Motion information of a user body portion can be determined based atleast in part upon sensory information received from imaging 2502, 2504or acoustic or other sensory devices. Control information iscommunicated to a system based in part on a combination of the motion ofthe portable device 2501 and the detected motion of the user determinedfrom the sensory information received from imaging 2502, 2504 oracoustic or other sensory devices. The virtual device experience can beaugmented in some implementations by the addition of haptic, audioand/or other sensory information projectors. For example, an optionalvideo projector 2520 can project an image of a page (e.g., virtualdevice) from a virtual book object superimposed upon a real worldobject, e.g., desk 2516 being displayed to a user via live video feed;thereby creating a virtual device experience of reading an actual book,or an electronic book on a physical e-reader, even though no book nore-reader is present. Optional haptic projector can project the feelingof the texture of the “virtual paper” of the book to the reader'sfinger. Optional audio projector can project the sound of a page turningin response to detecting the reader making a swipe to turn the page.Because it is a virtual reality world, the back side of hand 2514 isprojected to the user, so that the scene looks to the user as if theuser is looking at the user's own hand(s).

A plurality of sensors 2508, 2510 coupled to the sensory processingsystem 2506 to capture motions of the device 2501. Sensors 2508, 2510can be any type of sensor useful for obtaining signals from variousparameters of motion (acceleration, velocity, angular acceleration,angular velocity, position/locations); more generally, the term “motiondetector” herein refers to any device (or combination of devices)capable of converting mechanical motion into an electrical signal. Suchdevices can include, alone or in various combinations, accelerometers,gyroscopes, and magnetometers, and are designed to sense motions throughchanges in orientation, magnetism or gravity. Many types of motionsensors exist and implementation alternatives vary widely.

The illustrated system 2500 can include any of various other sensors notshown in FIG. 25 for clarity, alone or in various combinations, toenhance the virtual experience provided to the user of device 2501. Forexample, in low-light situations where free-form gestures cannot berecognized optically with a sufficient degree of reliability, system2506 may switch to a touch mode in which touch gestures are recognizedbased on acoustic or vibrational sensors. Alternatively, system 2506 mayswitch to the touch mode, or supplement image capture and processingwith touch sensing, when signals from acoustic or vibrational sensorsare sensed. In still another operational mode, a tap or touch gesturemay act as a “wake up” signal to bring the image and audio analysissystem 2506 from a standby mode to an operational mode. For example, thesystem 2506 may enter the standby mode if optical signals from thecameras 2502, 104 are absent for longer than a threshold interval.

It will be appreciated that the figures shown in FIG. 25 areillustrative. In some implementations, it may be desirable to house thesystem 2500 in a differently shaped enclosure or integrated within alarger component or assembly. Furthermore, the number and type of imagesensors, motion detectors, illumination sources, and so forth are shownschematically for the clarity, but neither the size nor the number isthe same in all implementations.

FIG. 28 is a representative method 2800 of integrating realthree-dimensional (3D) space sensing with a virtual reality head mounteddevice. Flowchart shown in FIG. 28 can be implemented at least partiallywith by one or more processors configured to receive or retrieveinformation, process the information, store results, and transmit theresults. Other implementations may perform the actions in differentorders and/or with different, varying, alternative, modified, fewer oradditional actions than those illustrated in FIG. 28. Multiple actionscan be combined in some implementations. For convenience, this flowchartis described with reference to the system that carries out a method. Thesystem is not necessarily part of the method.

At action 2810, a sensor attached to a virtual reality head mounteddevice is used to sense a first position of at least one hand in a firstreference frame of a three-dimensional (3D) sensory space at a firsttime t0. In some implementations, the tracking of the hand includestracking fingers of the hand.

At action 2820, display of a first virtual representation of the hand atthe first position is caused. In one implementation, the first virtualrepresentation is rendered in a virtual environment of the virtualreality head mounted device.

At action 2830, a second position of the hand and at least some of thefingers is sensed in the 3D sensory space at a second time t1 that isdifferent from the first position. This occurs in response torepositioning of the virtual reality head mounted device and theattached sensor due to body movement. In one implementation, the handdoes not move in the 3D sensory space between t0 and t1.

At action 2840, display of a second virtual representation of the handat an actual second position is caused by sensing motion of the attachedsensor and calculating a second reference frame that accounts forrepositioning of the attached sensor, calculating a transformation thatrenders the first position in the first reference frame and the secondposition in the second reference frame into a common reference frame,and transforming the first and second positions of the hand into thecommon reference frame. In one implementation, the common referenceframe has a fixed point of reference and an initial orientation of axes,whereby the sensed second position is transformed to the actual secondposition.

In one implementation, the common reference frame is a world referenceframe that does not change as the attached sensor is repositioned. Inanother implementation, the common reference frame is the secondreference frame.

The method further includes transforming the first and second positionsof the hand into the common reference frame further includes applying anaffine transformation. It also includes determining the orientation ofthe hand at the first position with respect to the first reference frameand causing the display of the hand accordingly. In yet anotherimplementation, the method includes, determining the orientation of thehand at the second position with respect to the second reference frameand causing the display of the hand accordingly.

In one implementation, the determining the position of the hand at thefirst position further includes calculating a translation of the handwith respect to the common reference frame and causing the display ofthe hand accordingly. In another implementation, the determining theposition of the hand at the second position further includes calculatinga translation of the hand with respect to the common reference frame andcausing the display of the hand accordingly.

This method and other implementations of the technology disclosed caninclude one or more of the following features and/or features describedin connection with additional methods disclosed. In the interest ofconciseness, the combinations of features disclosed in this applicationare not individually enumerated and are not repeated with each base setof features. The reader will understand how features identified in thissection can readily be combined with sets of base features identified asimplementations in sections of this application.

Other implementations can include a non-transitory computer readablestorage medium storing instructions executable by a processor to performany of the methods described above. Yet another implementation caninclude a system including memory and one or more processors operable toexecute instructions, stored in the memory, to perform any of themethods described above.

FIG. 29 depicts a flowchart 2900 of integrating real three-dimensional(3D) space sensing with an augmented reality head mounted device.Flowchart shown in FIG. 29 can be implemented at least partially with byone or more processors configured to receive or retrieve information,process the information, store results, and transmit the results. Otherimplementations may perform the actions in different orders and/or withdifferent, varying, alternative, modified, fewer or additional actionsthan those illustrated in FIG. 29. Multiple actions can be combined insome implementations. For convenience, this flowchart is described withreference to the system that carries out a method. The system is notnecessarily part of the method.

At action 2910, a sensor attached to the augmented reality head mounteddevice is used to sense a first position of at least one hand, at afirst time to, in a first reference frame of a three-dimensional (3D)sensory space located in a real environment. In one implementation,tracking the hand includes tracking fingers of the hand.

At action 2920, data representing a first virtual representation of thehand at the first position is generated. In one implementation, thefirst virtual representation is rendered in a virtual environment of theaugmented reality head mounted device superimposed on the realenvironment.

At action 2930, a second position of the hand and at least some of thefingers is sensed in the 3D sensory space at a second time t1. In oneimplementation, the second position is different from the firstposition. This occurs in response to repositioning of the augmentedreality head mounted device and the attached sensor due to bodymovement. In one implementation, the hand does not move in the 3Dsensory space between t0 and t1.

At action 2940, data representing a second virtual representation of thehand at an actual second position is generated by sensing motion of theattached sensor and calculating a second reference frame that accountsfor repositioning of the attached sensor, calculating a transformationthat renders the first position in the first reference frame and thesecond position in the second reference frame into a common referenceframe, and transforming the first and second positions of the hand intothe common reference frame. In one implementation, the common referenceframe has a fixed point of reference and an initial orientation of axes,whereby the sensed second position is transformed to the actual secondposition.

In one implementation, the common reference frame is a world referenceframe that does not change as the attached sensor is repositioned. Inanother implementation, the common reference frame is the secondreference frame.

In some implementations, the transforming the first and second positionsof the hand into the common reference frame further includes applying anaffine transformation. In other implementations, the method furtherincludes determining the orientation of the hand at the first positionwith respect to the first reference frame and causing interactionbetween the hand and the augmented reality accordingly. In yet otherimplementations, the method includes determining the orientation of thehand at the second position with respect to the second reference frameand causing interaction between the hand and the augmented realityaccordingly.

In one implementation, the determining the position of the hand at thefirst position further includes calculating a translation of the handwith respect to the common reference frame and causing interactionbetween the hand and the augmented reality accordingly. In anotherimplementation, the determining the position of the hand at the secondposition further includes calculating a translation of the hand withrespect to the common reference frame and causing interaction betweenthe hand and the augmented reality accordingly.

This method and other implementations of the technology disclosed caninclude one or more of the following features and/or features describedin connection with additional methods disclosed. In the interest ofconciseness, the combinations of features disclosed in this applicationare not individually enumerated and are not repeated with each base setof features. The reader will understand how features identified in thissection can readily be combined with sets of base features identified asimplementations in sections of this application.

Other implementations can include a non-transitory computer readablestorage medium storing instructions executable by a processor to performany of the methods described above. Yet another implementation caninclude a system including memory and one or more processors operable toexecute instructions, stored in the memory, to perform any of themethods described above.

FIG. 30 illustrates a flowchart 3000 of a representative method ofintegrating real three-dimensional (3D) space sensing with a headmounted device that renders a virtual background and one or more virtualobjects is described. Flowchart shown in FIG. 30 can be implemented atleast partially with by one or more processors configured to receive orretrieve information, process the information, store results, andtransmit the results. Other implementations may perform the actions indifferent orders and/or with different, varying, alternative, modified,fewer or additional actions than those illustrated in FIG. 30. Multipleactions can be combined in some implementations. For convenience, thisflowchart is described with reference to the system that carries out amethod. The system is not necessarily part of the method.

At action 3010, a sensor attached to the head mounted device is used tosense a first position of at least one hand, at a first time, in a firstreference frame of a three-dimensional (3D) sensory space. In oneimplementation, tracking the hand includes tracking fingers of the hand.

At action 3020, a second position of the hand and at least some of thefingers is sensed at a second time.

At action 3030, responsive to repositioning of the head mounted deviceand the attached sensor due to body movement, motion of the attachedsensor is sensed and a second reference frame that accounts forrepositioning of the attached sensor is calculated.

At action 3040, a transformation is calculated, which renders the firstposition in the first reference frame and the second position in thesecond reference frame into a common reference frame.

At action 3050, the first and second positions of the hand aretransformed into the common reference frame. In one implementation, thecommon reference frame has a fixed point of reference and an initialorientation of axes.

In one implementation, the common reference frame is a world referenceframe that does not change as the attached sensor is repositioned. Inanother implementation, the common reference frame is the secondreference frame.

In some implementations, the attached sensor is integrated into a unitwith the virtual reality head mounted device. In other implementations,the transforming the first and second positions of the hand into thecommon reference frame further includes applying at least one affinetransformation.

This method and other implementations of the technology disclosed caninclude one or more of the following features and/or features describedin connection with additional methods disclosed. In the interest ofconciseness, the combinations of features disclosed in this applicationare not individually enumerated and are not repeated with each base setof features. The reader will understand how features identified in thissection can readily be combined with sets of base features identified asimplementations in sections of this application.

Other implementations can include a non-transitory computer readablestorage medium storing instructions executable by a processor to performany of the methods described above. Yet another implementation caninclude a system including memory and one or more processors operable toexecute instructions, stored in the memory, to perform any of themethods described above.

FIG. 31 depicts a flowchart 3100 of re-rendering of a hand in anaugmented reality head mounted device. Flowchart shown in FIG. 31 can beimplemented at least partially with by one or more processors configuredto receive or retrieve information, process the information, storeresults, and transmit the results. Other implementations may perform theactions in different orders and/or with different, varying, alternative,modified, fewer or additional actions than those illustrated in FIG. 31.Multiple actions can be combined in some implementations. Forconvenience, this flowchart is described with reference to the systemthat carries out a method. The system is not necessarily part of themethod.

At action 3110, an offset between expected positions of one or more eyesof a wearer of a head mounted device and a sensor attached to the headmounted device for sensing a first position of at least one hand in athree-dimensional (3D) sensory space, including tracking fingers of thehand is determined.

At action 3120, using the sensor using the sensor, sensing a position ofthe hand in the three-dimensional (3D) sensory space. In oneimplementation, tracking the hand includes tracking fingers of the hand.

At action 3130, a transformation is calculated, which transforms thesensed position of the hand into a re-rendered position of the hand aswould appear to the wearer of the head mounted device if the wearer werelooking at the actual hand. In an implementation, the offset determinedin action 3110 is used in the transformation.

At action 3140, the depicting to the wearer of the head mounted devicethe re-rendered hand.

Noteworthy is that additional positions of the hand can be sensed, andfrom multiple positions of the hand, motion and gestures can bedetermined. Yet further, the offset can be applied to transform theposition of the hand in multiple positions, thereby providing are-rendered image hand of a gesture to the wearer. Still yet further,the transform can be constructed to account for viewing angledifferences between eyes of the wearer and the sensor.

In some implementations, the attached sensor is integrated into a unitwith the virtual reality head mounted device. In other implementations,the transforming the sensed positions of the hand further includesapplying at least one affine transformation.

This method and other implementations of the technology disclosed caninclude one or more of the following features and/or features describedin connection with additional methods disclosed. In the interest ofconciseness, the combinations of features disclosed in this applicationare not individually enumerated and are not repeated with each base setof features. The reader will understand how features identified in thissection can readily be combined with sets of base features identified asimplementations in sections of this application.

Other implementations can include a non-transitory computer readablestorage medium storing instructions executable by a processor to performany of the methods described above. Yet another implementation caninclude a system including memory and one or more processors operable toexecute instructions, stored in the memory, to perform any of themethods described above.

CONCLUSIONS AND SPECIFIC IMPLEMENTATIONS

We describe a system and various implementations for of realisticdisplacement of a virtual object to render a realistic representation ofa hand in a three-dimensional (3D) sensory space as a virtual object ina virtual space.

In one implementation, described is a system including, a head mounteddevice depicting at least a visual presentation to a wearer. Ahand-gesture sensor is attached to the head mounted device. A processorand a computer readable storage medium are coupled to the head mounteddevice and the hand-gesture sensor. The storage medium stores computerinstructions configured for performing a variety of tasks. For example,the system performs determining an offset between expected positions ofone or more eyes of a wearer of a head mounted device and an actualposition of a hand-gesture sensor attached to the head mounted device.Using the hand-gesture sensor, the system computes a sensed position ofat least one hand in a three-dimensional (3D) sensory space. Thecomputing includes determining positions of fingers, thumb and palm ofthe hand. Using the offset, the system transforms the sensed position ofthe hand into a re-rendered position of the hand. The re-renderedposition of the hand places in the 3D sensory space the positions of thefingers, thumb and palm of the re-rendered position of the hand at theoffset with respect to the sensed position of the hand such that thewearer of the head mounted device perceives the re-rendered position ofthe hand situated in the 3D sensory space as expected by the wearer whenthe wearer is looking at the actual hand in the 3D sensory space. Thesystem depicts to the wearer of the head mounted device a re-renderedimage hand using the re-rendered position of the hand.

Some additional implementations and features include:

-   -   In some implementations one or more additional positions of the        hand are sensed and motions or gestures are determining from        them. The offset is applied to the additional positions of the        hand to transform the sensed additional positions to re-rendered        positions of the hand as seen by the wearer, thereby providing        the re-rendered image hand having the motion or gesture of the        hand.    -   In some implementations an indication of quality of tracking is        sensed for the hand-gesture sensor. The indication of quality of        tracking indicating to the system whether the hand-gesture        sensor is tracking position or motion of the hand. A visual        indication corresponding to the indication of quality of        tracking is added to the re-rendered image hand. The visual        indication can provide the wearer with a visual que of how well        the hand-gesture sensor is tracking the hand.    -   In some implementations the indication of quality of tracking        includes an indication that the hand-gesture sensor is able to        recognize the hand in captured images.    -   In some implementations the visual indication corresponding to        the indication of quality of tracking includes a colored outline        circumscribed about the re-rendered image hand when the        hand-gesture sensor is able to recognize the hand in captured        images.    -   In some implementations the visual indication corresponding to        the indication of quality of tracking includes a colored outline        circumscribed about the re-rendered image hand when the        hand-gesture sensor is unable to recognize the hand in captured        images.    -   In some implementations the visual indication corresponding to        the indication of quality of tracking includes coloring the        re-rendered image hand a different color when the hand-gesture        sensor is able to recognize the hand in captured images than        when the hand-gesture sensor is unable to recognize the hand in        captured images.    -   In some implementations the system performs sensing an        indication of whether the hand has grabbed a virtual object; and        adds to the re-rendered image hand a visual indication        corresponding to the indication of whether the hand has grabbed        the virtual object. Such indication can provide the wearer with        a visual que of whether the virtual object is grabbed.

Other implementations include methods including performing the actionsof the system, non-transitory machine readable storage media storingprogram logic implementing such methods, substituents and componentsthereof, and devices incorporating any or combinations of the foregoing.

While the disclosed technology has been described with respect tospecific implementations, one skilled in the art will recognize thatnumerous modifications are possible. The number, types and arrangementof cameras and sensors can be varied. The cameras' capabilities,including frame rate, spatial resolution, and intensity resolution, canalso be varied as desired. The sensors' capabilities, includingsensitively levels and calibration, can also be varied as desired. Lightsources are optional and can be operated in continuous or pulsed mode.The systems described herein provide images and audio signals tofacilitate tracking movement of an object, and this information can beused for numerous purposes, of which position and/or motion detection isjust one among many possibilities.

Threshold cutoffs and other specific criteria for distinguishing objectfrom background can be adapted for particular hardware and particularenvironments. Frequency filters and other specific criteria fordistinguishing visual or audio signals from background noise can beadapted for particular cameras or sensors and particular devices. Insome implementations, the system can be calibrated for a particularenvironment or application, e.g., by adjusting frequency filters,threshold criteria, and so on.

Any type of object can be the subject of motion capture using thesetechniques, and various aspects of the implementation can be optimizedfor a particular object. For example, the type and positions of camerasand/or other sensors can be selected based on the size of the objectwhose motion is to be captured, the space in which motion is to becaptured, and/or the medium of the surface through which audio signalspropagate. Analysis techniques in accordance with implementations of thetechnology disclosed can be implemented as algorithms in any suitablecomputer language and executed on programmable processors.Alternatively, some or all of the algorithms can be implemented infixed-function logic circuits, and such circuits can be designed andfabricated using conventional or other tools.

Computer programs incorporating various features of the technologydisclosed may be encoded on various computer readable storage media;suitable media include magnetic disk or tape, optical storage media suchas compact disk (CD) or DVD (digital versatile disk), flash memory, andany other non-transitory medium capable of holding data in acomputer-readable form. Computer-readable storage media encoded with theprogram code may be packaged with a compatible device or providedseparately from other devices. In addition program code may be encodedand transmitted via wired optical, and/or wireless networks conformingto a variety of protocols, including the Internet, thereby allowingdistribution, e.g., via Internet download.

The terms and expressions employed herein are used as terms andexpressions of description and not of limitation, and there is nointention, in the use of such terms and expressions, of excluding anyequivalents of the features shown and described or portions thereof. Inaddition, having described certain implementations of the technologydisclosed, it will be apparent to those of ordinary skill in the artthat other implementations incorporating the concepts disclosed hereincan be used without departing from the spirit and scope of thetechnology disclosed. Accordingly, the described implementations are tobe considered in all respects as only illustrative and not restrictive.

What is claimed is:
 1. A system of realistic displacement of a virtualobject to render a realistic representation of a hand in athree-dimensional (3D) sensory space as a virtual object in a virtualspace, the system including: a head mounted device depicting at least avisual presentation to a wearer; a hand-gesture sensor attached to thehead mounted device; and a processor and a computer readable storagemedium storing computer instructions configured for performing:determining an offset between expected positions of one or more eyes ofa wearer of a head mounted device and an actual position of ahand-gesture sensor attached to the head mounted device; using thehand-gesture sensor, obtaining a sequence of images correlated toconstruct a 3-D solid model of the hand, including its position andshape, and using the 3-D solid model of the hand computing a sensedposition of hand in a three-dimensional (3D) sensory space, wherein thecomputing includes determining positions of fingers, thumb and palm ofthe hand; calculating a transformation matrix using the determinedoffset, such that the transformation matrix, when applied to the sensedposition of the hand, decreases a rendered size of the hand inaccordance with the determined offset; applying the transformationmatrix to the sensed position of the hand to transform the sensedposition of the hand into a re-rendered position of the hand, there-rendered position of the hand placing in the 3D sensory space thepositions of the fingers, thumb and palm of the re-rendered position ofthe hand at the offset with respect to the sensed position of the handsuch that the wearer of the head mounted device perceives there-rendered position of the hand situated in the 3D sensory space asexpected by the wearer when the wearer is looking at the actual hand inthe 3D sensory space; and depicting to the wearer of the head mounteddevice a re-rendered image hand using the re-rendered position of thehand.
 2. The system of claim 1, further configured to perform: sensingone or more additional positions of the hand and determining therefrommotion or gesture; and applying the offset to the additional positionsof the hand to transform the sensed additional positions to re-renderedpositions of the hand as seen by the wearer, thereby providing there-rendered image hand having the motion or gesture of the hand.
 3. Thesystem of claim 2, further configured to perform: sensing an indicationof quality of tracking for the hand-gesture sensor, the indication ofquality of tracking indicating whether the hand-gesture sensor istracking position or motion of the hand; and adding to the re-renderedimage hand a visual indication corresponding to the indication ofquality of tracking; thereby providing the wearer with a visual cue ofhow well the hand-gesture sensor is tracking the hand.
 4. The system ofclaim 3, wherein the indication of quality of tracking includes anindication that the hand-gesture sensor is able to recognize the hand incaptured images.
 5. The system of claim 4, wherein the visual indicationcorresponding to the indication of quality of tracking includes acolored outline circumscribed about the re-rendered image hand when thehand-gesture sensor is able to recognize the hand in captured images. 6.The system of claim 4, wherein the visual indication corresponding tothe indication of quality of tracking includes a colored outlinecircumscribed about the re-rendered image hand when the hand-gesturesensor is unable to recognize the hand in captured images.
 7. The systemof claim 1, wherein the transformation matrix is an affine matrix.
 8. Amethod of realistic displacement of a virtual object to render arealistic representation of a hand in a three-dimensional (3D) sensoryspace as a virtual object in a virtual space, the method including:determining an offset between expected positions of one or more eyes ofa wearer of a head mounted device and an actual position of ahand-gesture sensor attached to the head mounted device; using thehand-gesture sensor, obtaining a sequence of images correlated toconstruct a 3-D solid model of the hand, including its position andshape, and using the 3-D solid model of the hand computing a sensedposition of at least one hand in a three-dimensional (3D) sensory space,wherein the computing includes determining positions of fingers, thumband palm of the hand; calculating a transformation matrix using thedetermined offset, such that the transformation matrix, when applied tothe sensed position of the hand, decreases a rendered size of the handin accordance with the determined offset; applying the transformationmatrix to the sensed position of the hand to transform the sensedposition of the hand into a re-rendered position of the hand, there-rendered position of the hand placing in the 3D sensory space thepositions of the fingers, thumb and palm of the re-rendered position ofthe hand at the offset with respect to the sensed position of the handsuch that the wearer of the head mounted device perceives there-rendered position of the hand situated in the 3D sensory space asexpected by the wearer when the wearer is looking at the actual hand inthe 3D sensory space; and depicting to the wearer of the head mounteddevice a re-rendered image hand using the re-rendered position of thehand.
 9. The method of claim 8, further including: sensing one or moreadditional positions of the hand and determining therefrom motion orgesture; and applying the offset to the additional positions of the handto transform the sensed additional positions to re-rendered positions ofthe hand as seen by the wearer, thereby providing the re-rendered imagehand having the motion or gesture of the hand.
 10. The method of claim9, further including: sensing an indication of quality of tracking forthe hand-gesture sensor, the indication of quality of trackingindicating whether the hand-gesture sensor is tracking position ormotion of the hand; and adding to the re-rendered image hand a visualindication corresponding to the indication of quality of tracking;thereby providing the wearer with a visual cue of how well thehand-gesture sensor is tracking the hand.
 11. The method of claim 10,wherein the indication of quality of tracking includes an indicationthat the hand-gesture sensor is able to recognize the hand in capturedimages.
 12. The method of claim 11, wherein the visual indicationcorresponding to the indication of quality of tracking includes acolored outline circumscribed about the re-rendered image hand when thehand-gesture sensor is able to recognize the hand in captured images.13. The method of claim 11, wherein the visual indication correspondingto the indication of quality of tracking includes a colored outlinecircumscribed about the re-rendered image hand when the hand-gesturesensor is unable to recognize the hand in captured images.
 14. One ormore non-transitory computer readable media having instructions storedthereon for performing realistic displacement of a virtual object torender a realistic representation of a hand in a three-dimensional (3D)sensory space as a virtual object in a virtual space, the performingincluding: determining an offset between expected positions of one ormore eyes of a wearer of a head mounted device and an actual position ofa hand-gesture sensor attached to the head mounted device; using thehand-gesture sensor, obtaining a sequence of images correlated toconstruct a 3-D solid model of the hand, including its position andshape, and using the 3-D solid model of the hand computing a sensedposition of at least one hand in a three-dimensional (3D) sensory space,wherein the computing includes determining positions of fingers, thumband palm of the hand; calculating a transformation matrix using thedetermined offset, such that the transformation matrix, when applied tothe sensed position of the hand, decreases a rendered size of the handin accordance with the determined offset; applying the transformationmatrix to the sensed position of the hand to transform the sensedposition of the hand into a re-rendered position of the hand, there-rendered position of the hand placing in the 3D sensory space thepositions of the fingers, thumb and palm of the re-rendered position ofthe hand at the offset with respect to the sensed position of the handsuch that the wearer of the head mounted device perceives there-rendered position of the hand situated in the 3D sensory space asexpected by the wearer when the wearer is looking at the actual hand inthe 3D sensory space; and depicting to the wearer of the head mounteddevice a re-rendered image hand using the re-rendered position of thehand.
 15. The non-transitory computer readable media of claim 14, theinstructions further implementing performing: sensing one or moreadditional positions of the hand and determining therefrom motion orgesture; and applying the offset to the additional positions of the handto transform the sensed additional positions to re-rendered positions ofthe hand as seen by the wearer, thereby providing the re-rendered imagehand having the motion or gesture of the hand.
 16. The non-transitorycomputer readable media of claim 15, the instructions furtherimplementing performing: sensing an indication of quality of trackingfor the hand-gesture sensor, the indication of quality of trackingindicating whether the hand-gesture sensor is tracking position ormotion of the hand; and adding to the re-rendered image hand a visualindication corresponding to the indication of quality of tracking;thereby providing the wearer with a visual cue of how well thehand-gesture sensor is tracking the hand.
 17. The non-transitorycomputer readable media of claim 16, wherein the indication of qualityof tracking includes an indication that the hand-gesture sensor is ableto recognize the hand in captured images.
 18. The non-transitorycomputer readable media of claim 17, wherein the visual indicationcorresponding to the indication of quality of tracking includes acolored outline circumscribed about the re-rendered image hand when thehand-gesture sensor is able to recognize the hand in captured images.19. The non-transitory computer readable media of claim 17, wherein thevisual indication corresponding to the indication of quality of trackingincludes a colored outline circumscribed about the re-rendered imagehand when the hand-gesture sensor is unable to recognize the hand incaptured images.
 20. The non-transitory computer readable media of claim17, wherein the visual indication corresponding to the indication ofquality of tracking includes coloring the re-rendered image hand adifferent color when the hand-gesture sensor is able to recognize thehand in captured images than when the hand-gesture sensor is unable torecognize the hand in captured images.
 21. The non-transitory computerreadable media of claim 15, the instructions further implementingperforming: sensing an indication of whether the hand has grabbed avirtual object; and adding to the re-rendered image hand a visualindication corresponding to the indication of whether the hand hasgrabbed the virtual object; thereby providing the wearer with a visualcue of whether the virtual object is grabbed.
 22. The non-transitorycomputer readable media of claim 21, the instructions furtherimplementing performing: depicting a stretched version of the virtualobject grabbed.